Operation Oil Spill was introduced to MvM alongside Operation Gear Grinder, and it is currently the only Intermediate tour.

In this guide, I will cover class roles and such as if you are a newer player to the gamemode before actually getting in detail about the actual tour itself. I still advise players that have done some Boot Camp to read through class details as it is very likely there are things that you may not know about certain classes, or have a misinformed view of.

As a disclaimer, this guide will also give you what is arguably the most effective methods to taking on these missions, but do not discredit any other possible setups and strategies. Better players in MvM are capable of playing with more varied setups than sticking with the same classes and the same strategies all the time. The community has developed what is called the "meta," which is a rigid class structure and loadouts that is the most common method to playing missions. The meta is most strictly enforced in the Two Cities tour (the tour for which the meta is actually inefficient), and it is very likely you will be kicked for breaking meta there.

The meta is not always the most efficient setup, and I very highly advise not getting used to it. Bad players in MvM will generally be more adamant in defending and enforcing the meta, and you should avoid becoming like them. Would you really find it fun to play the same missions with the same classes with the same loadouts over and over and over and over and over and over and over and over and over again fun? There are actually players who go for 100 or more tours sticking to the meta, and still perform horribly even with the meta classes. Breaking meta often helps to better understand class roles and how to effectively play your class, and to support the other classes as well. The meta has also created a cancerous plethora of misconceptions and misinformation about the gamemode as well.

If possible, play with friends. You won't have to worry about dealing with random players that are likely to try to shove the meta down your throat. And always be willing to try different setups.

Remember, don't be that one person that complains about having a low tour playing a non-meta class despite having good upgrades and a good loadout and seem to know what they're doing. And don't end up being that one high tour with a shitty attitude towards low tours, despite being less skilled than one. For example, this 34 tour heavy who claims I got carried all my expert tours:

Also, very important, read this

I started writing this guide before the infinite refund existed. I, as well as a good deal of other players, was not too happy to see this change to MvM, as it scales down the difficulty way too much, especially for tours that were introduced before refunds existed. To be able to get better, it's preferable you play without using refunds, and stick with a class from start to finish, as it will force you to adjust to waves that your class is not suited for - there is a limit to how good you can get at something without some challenge to it. I'd suggest that you play with a team of people who will all agree not to use the refund, or make very, very minimal use of it.

Unlike PvP, MvM is a co-op gamemode where you will be pitted against hordes of robots, with you fighting alongside up to 5 other team members. The robots will try to carry a bomb to a bomb hatch near your spawn, and your goal is to stop them and clear out all the bots in each wave. Waves are made up of an already determined group of robots that will not change every time you replay the mission, thus waves are very predictable. The robots will also take a specified path to the hatch, indicated by blue holographic arrows that are visible during setup. You will also have money to put into upgrades, and you will need to upgrade in a manner that will help you clear out the robots more efficiently.

The difference between Boot Camp and Mann Up is that Boot Camp is completely free, but in Mann Up you will need to have a Tour of Duty ticket to be able to queue up for a mission. Your ticket will not be used up unless you complete the mission, so you do not have to worry too much about not completing a mission for any reason - the only thing you will lose is some of your time. In Mann Up there are tours, and in each tour there are a set of missions. At the end of each mission in a tour you have never played, you will be given a badge that will track your tour completion status; replaying a mission already done in that tour will not use up tickets. To complete a tour, you will have to do all the missions in the tour; at the end of each mission, you will get very cheap loot, and in some rare cases a cosmetic, paint, etc., but at the end of each tour, you will get special loot. Once you complete a tour, you can start the missions all over again for more loot, and special loot at the end of each tour.

Currently, there are 5 tours: Oil Spill (Intermediate), Steel Trap (Advanced), Mecha Engine (Advanced), Two Cities (Advanced), and Gear Grinder (Expert). Each tour has its own badge, and if you notice, the badge has a level, which corresponds to the number of tours you have completed.

Here are mine:
https://steamhost.cn/steamcommunity_com/id/jrobofficial/inventory/#440_2_2854438722
https://steamhost.cn/steamcommunity_com/id/jrobofficial/inventory/#440_2_3807877638
https://steamhost.cn/steamcommunity_com/id/jrobofficial/inventory/#440_2_3830736966
https://steamhost.cn/steamcommunity_com/id/jrobofficial/inventory/#440_2_3659575121
https://steamhost.cn/steamcommunity_com/id/jrobofficial/inventory/#440_2_3801672195

Now, you may have noticed by now that my Oil Spill badge is only level 2 and ask, "hey, if you've only completed one tour of this so far, why would you make a guide of it already?" Gear Grinder takes place on the same maps as Oil Spill, and the same strategies are very much applicable to Oil Spill as well, and having played different tours, it is easier to analyze waves and formulate the best setup to finish missions in the most efficient way possible. And as mentioned before, repeating a mission in a tour does not use a ticket or count towards tour completions, so don't always take tour count at face value as some players will often have one mission in a tour uncompleted and simply just repeat the rest over and over again just for fun.

Each class will obviously serve a certain role in the gamemode. The most basic roles you're going to want to be running are: money collection, ammo supply, tank damage, crowd control damage, giant damage, and medic picking/killing.

Crowd controllers are classes that specialize in dealing with multiple targets at once. Compared to Heavy, they don't have as high of a damage output on single targets, but their attacks have an area of effect, which with more targets will practically boost their damage output to be higher than a Heavy's or a sentry. The goal of crowd control classes is to bring down the amount of robots in a horde to where a Heavy and sentry can easily finish off the rest. Crowd control classes, however, will not be as effective with giants. The crowd control classes are Soldier, Demo, Sniper, and to some extent, Pyro.

Giant Robots are a thing in MvM, and you will need someone who can output large amounts of damage in a short period of time. The two classes that have the best single target DPS are the Heavy and the Spy. Heavy starts out with a huge 540 DPS at close range (756 DPS at max Firing Speed) - this makes him the ideal giant killer. Spy with maxed Penetration upgrades on his knife will do 938 damage per stab on a giant, however, take note that giants will turn around and start attacking after a couple stabs (upgrade Swing Speed so you can get more stabs in). Another good class for dealing with giants is a Backburner Pyro; while the giant is distracted, Pyro can get behind the giant for easy crits (giving him 402 DPS without any upgrades, and 861 DPS with max damage), and unlike Spy, the giant won't turn around to attack the Pyro unless the Pyro is the only one attacking it or there is no one else in his field of view.

Medic picking does not mean pick the Medic class. Medic pickers are classes that can kill off Uber Medic robots before they can use their uber. Since Uber Medics will uber if they or their patient drops below half health, you will need to kill them in one shot, or very, very quickly. Demoman is one of the medic pickers, as he can lay down a group of stickies, and then detonate them to deal more than enough damage to kill off an Uber Medic or Medics in a single shot. Sniper with Explosive Headshot upgrades can also achieve this by shooting at either the Medic or its patient, and the Explosive Headshot will kill the Medic as long as it is in range of the "explosion" - and yes, you can kill more than one Medic on the target this way. Spy can also backstab Medics, but is not as efficient of a medic picker as Demo or Sniper as he can only deal with one at a time; if bots only have a single Medic on them, Spy can pass as a medic picker. With enough damage upgrades, a Soldier is capable of picking off medics, but it is still advised to leave it to Demo or Sniper, unless they're currently dead or you are without one.

Tanks are also a thing in MvM. They do not attack back, they simply roll slowly to the bomb, and you have to put enough damage on them before they can get to the hatch and deploy their bomb. Heavy would be an ideal class for this with his high DPS, that is, if it weren't for the fact that his minigun does 75% less damage to tanks; this puts Heavy below Demo on tankbusting if the Demo is upgrading and using this Grenade Launcher, and above Demo in tankbusting if Demo is upgrading and using his Stickybomb Launcher. The three best classes for tankbusting are Scout, Soldier, and Pyro. A Scout with an upgraded Soda Popper or Shortstop (Soda Popper is cheaper), a Soldier with the Beggar's Bazooka, and a Pyro with the Phlogistinator have the best DPS to deal with tanks, with Pyro being the cheapest to upgrade.

You will obviously need someone to collect money so you can buy more upgrades. Scout is the best at this, and Spy is also good at it (better in some specific cases). And you will need to have an ammo supply so you can keep killing bots, which is why you will want to be running an Engineer.

You need someone to collect money, right? Scout is the strongest class for collecting money in most cases, especially considering that money heals the Scout, and will overheal him too (you can have up to 600-700 health from this, and sometimes may even reach or pass 800). Scout is also capable of putting out large amounts of tank damage, and fills support roles well with mad milk, marking bots for death with the Fan o' War (or Sandman with the mark for death upgrade), and drawing robot aggro away from teammates to mitigate the damage the team is taking. Some other things you will want to make sure you're doing as a Scout includes picking off Sniper robots harassing the team, picking off stray bots with the bomb if your engy isn't keeping his sentry on it (or is currently dealing with a Sentry Buster), and contributing to damage some if your team is lacking in it. It is generally ill-advised to run more than one scout, but this does not mean it isn't doable - I've played entire Advanced missions with more than one scout, even teams of all Scouts.

Preferred loadout:

Soda Popper/Shortstop/Force-A-Nature
Mad Milk
Fan o' War/Sandman

(Bonk and Crit-a-Cola are also viable options, but players will generally want milk, and milk will help keep your teammates alive more)

Common Misconceptions:

"Scout needs to get ALL the money!" - this is very much untrue. While you will want scout to get as much money as possible, it is fine if the scout misses a little. Just make sure they're not missing an insane amount of money each wave, and a couple bonuses would be nice.

"We don't need to worry about money last wave, you can switch, scout" - this implies scout is a weak class when it comes to damage; this is entirely untrue. Scout is one of the 3 greatest tankbusters, and is capable of dealing good damage to bots. And don't forget, he still has milking and marking, too.

Another thing to note is that the mark for death upgrade on the Sandman doesn't just apply to the ball like the description says, hitting bots with the bat works as well. And don't forget, you can only mark one bot at a time, so don't bother with getting swing speed upgrades on the fan, or upgrading the Sandman too much.

"Scouts can't do good damage!"


"We don't need two Scouts!"


"We don't need to worry about money last wave, you can switch, scout"

A lot of bots are going to come in groups, and you're going to need some crowd control. Soldier fits the crowd control damage role perfectly as his launchers deal splash damage; avoid the Air Strike and Direct Hit as these two launchers will reduce your crowd control capability, and Heavy is a much better option for dealing with single targets. Soldier also has banners to support his team. Overall, soldier is a fairly straightforward class - do damage and use your banner. Soldier is also one of the three strongest tankbusters when he runs the Beggars Bazooka. However, Soldier is not a very strong class with only $400 of upgrades, which all Oil Spill missions start you out on. It is a common strategy in Gear Grinder to start out as an upgradeless Heavy for the first wave or two, and switch over to Soldier with enough credits to play more effectively, and this will work as well in Oil Spill.

Preferred Loadout:

Stock/Black Box/Beggars Bazooka
Concheror/Buff Banner
Anything that isn't Pain Train

Avoid using the Rocket Jumper, Liberty Launcher, Air Strike, and Direct Hit, unless for some reason you and some friends want to jokingly use bad loadouts as a challenge.

I cannot even begin to stress how great the Beggars Bazooka is. Never mind the projectile deviation or not being able to get ammo from dispensers when active - this thing has insane DPS compared to the other launchers. You should be up closer to bots to get full damage ramp-up, which mitigates the deviation as well, and why would you need to have that precise of aim when you're dealing with hordes of bots, which the class is built for - crowd controlling. You may not be able to get ammo from dispensers while you are holding the weapon out, but it isn't hard at all to just switch to your secondary or melee for a second or two - you could easily just use that time to use your banner while the dispenser restocks your ammo. The Beggars' downsides are negligible in practice.

Common Misconceptions:

You may see a lot of Soldiers get more than one Rocket Specialist. Do not do this. Any more than a single tick is a waste. You get the stun effect and maximum ramp up on direct hits (no, not the weapon, mind you) on the first tick, and subsequent upgrades of it will only make your rockets slightly faster, and give it slightly more blast radius, which you won't need as your current explosion radius will be more than sufficient for dealing with hordes.

"Soldier needs to use the Buff Banner" - very much untrue. All the banners are viable. However, the Battalion's Backup becomes less effective in later waves when your teammates should have resistances, especially for crit. Concheror is a very strong banner that increases the survivability of your team. Buff Banner is a better option in cases where your team is capable of surviving well without the conch, and waves where you need damage, like tank waves, or melee bot spam.

"Air Strike is good for tanks" - no. No it is not. Just no.

Why Beggars + Conch is the best combo

See these for an explanation as to why:

Tanks are a thing in MvM, and you're going to want to have someone who can deal with them effectively. Pyro is the cheapest to upgrade out of the three greatest tankbusters, and the Phlogistinator makes taking down tanks even faster. Pyro is also capable of dealing good crowd control damage (just make sure the bots don't aggro on you before you jump in, else you'll be a dead pyro quick without enough upgrades). Pyro also has airblast which can save teammates from some projectiles, bomb resets, and keep ubered bots back, but use it sparingly - a pyro that does nothing but airblast can be a nuisance to your team, and especially don't bother airblasting Sentry Busters, unless the engy can't move the sentry because he's dead, or it's currently blocking a Giant Scout; remember, moderation is key - don't abuse it. Pyro's Backburner is also very good for doing damage to distracted giant robots since you get free crits from it.

Preferred Loadout:

Anything that isn't Degreaser
N/A (though Detonator is good for mobility and getting Mmmph from a distance at points)
Homewrecker/Neon Annihilator/Powerjack

The Degreaser is an absolutely terrible weapon in MvM as it has less damage, and fast weapon switch is practically useless in MvM.

Common Misconceptions:

"pyro iz uzelezz" - obvious Two Shitties player alert.

"Pyro is bad early on" - if you know how to abuse robot aggro, you can easily play pyro early on without resistances. A move speed or two and a health on kill goes a long way, too, just make sure you have damage (NOT BURN DAMAGE) maxed by the first tank wave.

"Pyro is useless!"

Like Soldier, he is a great crowd control class, but unlike Soldier, he can lay a large trap and detonate behind cover to take out large hordes of more dangerous bots while Soldier will have to expose himself; for this reason, Demo can spend a little less on resistances and still be effective. Also, using traps, Demo is great for killing off Uber Medics fast enough so they don't pop their uber. Despite what the general playerbase of Two Shitties thinks, Demo is NOT the class you want to be attacking the tank, especially if he needs to be dealing with crowd control or Uber Medics; also, despite Heavy's 75% minigun damage reduction against tanks, a Demoman using stickies will still have a lower DPS against tanks (grenades, on the other hand, will have a higher DPS).***

Preferred Loadout:

Anything that isn't B.A.S.E. Jumper
Stock/Scottish Resistance
Anything that isn't Pain Train, Persian Persuader, or lowers health

Expert players will generally prefer using the Scottish Resistance, as you can cover more area with the 6 extra stickies you can place. Eyelander and reskins are viable melees, but are not advised if you have trouble getting heads or staying alive, especially with the reduced health. Some players may want to run the Bootlegger for the extra health, as you can manage to play using stickies alone, and the extra health helps with survivability.

Common Misconceptions:

"Demoman shouldn't upgrade grenades" - grenade Demo is a viable playstyle, as long as you're using stickies when there are Uber Medics, and you are not spreading your upgrades accross both your primary and Stickybomb Launcher. When there are no Uber Meds, you can even use the Charge n' Targe for the free resistance.

"Demo you need to crit your stickies before the wave starts" - you do not need to do this (you really should not do this), especially when it means wasting $100 on a crit canteen. A trap of normal stickies will be sufficient enough to pick off Medics, and this will be overkill when dealing with smaller bots. The only time getting crit canteens for this is to deal with Giant Medics in a single shot in later waves if you don't have a Spy to deal with them, and even then is advised you use the Scottish Resistance to do so.

Damage is very important in MvM, and Heavy is good at putting out large amounts of it. Heavy is a strong class without upgrades, the strongest giant killer first wave, too, as he starts out with 540 DPS at close range on his stock minigun without upgrades. Heavy is a pretty straightforward class, and is easiest for beginners to play, although a good Heavy is a huge asset as damage is key in MvM. Heavy can also use his body and high health to block giants, especially Giant Scouts, to keep them from progressing with the bomb; this is especially easier if a Scout throws Mad Milk on the giants. Heavy's low mobility will be a problem when you start to get low on ammo, so it would be best to stay near the Engineer's dispenser (just don't hug it the entire time, you do a lot more damage up close to your target, so move up to deal more damage, and back when you need ammo). Since damage is very important in MvM, it is actually common to see more than on a team in Gear Grinder, and is very effective to have more than one on maps like Mannhattan, Mannworks, and Decoy, maps that favor Heavy.

One very important function that you need to be aware of is damage falloff; most classes are affected by it. The farther away you are from your target, the less damage you do, and the minigun's accuracy only makes it worse. To get the most DPS out of the minigun, you have to be up close and personal with the bots; this is especially important when dealing with giants. A Heavy with maxed Firing Speed upgrades can kill giant Black Box Soldiers before they can reload if constantly unloading bullets into them at close range.

Preferred loadout:

Stock/Brass Beast
Doesn't matter
Anything that isn't Warrior's Spirit

The Huo-Long Heater isn't necessarily a bad minigun since it doesn't suffer any damage penalties, but its extra ammo consumption will keep you tied to the dispenser a little longer; if you have a good Engineer that makes sure to keep the dispenser near you, this won't be too big of a problem, but it is still advised to use stock instead. Brass Beast may do more damage, but will make it harder to avoid projectiles, and changing position with it is harder than with stock. By all means, avoid using the Tomislav and Natascha. The Tomislav practically does 20% less damage (firing speed essentially equals damage output), and its upside is near useless since bots don't hear your minigun revving, and the increased rev up speed is negligible of a bonus in MvM. The Natascha does a straight 25% less damage, and you should be bodyblocking in the first place, making the slowdown less useful, so it is also very much ill-advised. Also, keep in mind that the Warrior's Spirit reduces your health by 20, and doesn't provide any passive bonuses; since you shouldn't be using melee as Heavy, avoid using this melee.

Common misconceptions:

"Heavy needs a Medic to be effective" - health on kill upgrades are a thing, the dispenser gives health, and Scout can milk giants which is sufficient enough for Heavy to tank most giants. Heavy also has the Destroy Projectiles upgrade to mitigate the amount of explosives coming his way. No, Heavy does not need a Medic to be effective.

Also, unknown to many players, currently, the second tick of Firing Speed on the minigun is bugged and doesn't work. The first, third, and fourth ticks of the upgrade will still work, however.

Learn to play well without a Medic, and then consider what you'll be capable of when you do have one pocketing you. "bad med + bad heavy = 1 player with basic mvm knowledge." -Radioactive Panda

Your team will need to have a way of refilling ammo so they can keep a front line; as Engineer, your dispenser provides a source of ammo that can be moved to wherever it is needed. Your sentry will also provide some extra damage, as well as help to keep bots that your teammates may miss from running off with the bomb, and also for blocking Giant Scouts (and giants in general, especially with the Wrangler). Your teleporters will also be helpful to get teammates back to the front lines faster to help keep the defensive line. Take note that giant robots will destroy dispensers and teleporters on contact, but will not sentries; also, note that robots will not ever actively attack teleporters, so if the front line is lost and the teleporter is in a place where there are hordes of bots, it may be a good idea to just destroy the exit if it can't be moved so that your teammates don't teleport into a bot horde and get killed (and it'll also keep them from killing bots up front, and it is a good idea to prevent that to make Scout's job easier). Remember the general rule of thumb: keep your dispenser near the team in a place where it won't take a lot of damage, and keep the sentry where it can kill the bomb carrier.

Things to avoid as an Engineer:

Every now and then, a Sentry Buster will spawn. It will run straight towards your sentry and will explode on it. It won't attack and can't be blocked by your teammates as it clips through them. The best way to deal with busters is to pick up your sentry, lead it away from your team, and let it get near you; when it is close to you, it will start the detonation process, and you will have enough time to get out of its blast radius.

Also, do not be the kind of Engineer that sets up at spawn from the get-go. This is a very useless kind of Engineer, as they will not help hold a front line, and most times will not share their dispenser with the team.

Do not get the Disposable Sentry upgrade. It is practically a mini sentry, and does not put out a decent amount of damage, especially for $500.

The Firing Speed upgrade is a bugged upgrade and will only work at the first tick of the upgrade for un-wrangled sentries, and the second only works for wrangled sentries; the third tick of the upgrade is completely useless.

Preferred loadout:

Rescue Ranger (or Pomson/Frontier Justice)
Wrangler/Short Circuit
Stock/Jag

In most cases, the Rescue Ranger will be the best primary since you can repair buildings from a distance, as well as pick them up from a distance (especially useful when dealing with busters if you can't get to your sentry in time). Pomson is great for waves where there are Giant Medics, as you can help keep them from ubering. Avoid using the Eureka Effect at all costs, as it suffers greatly from a repair rate penalty, and teleporting back to spawn is not worth the downsides. Also avoid using the Gunslinger for the same reason you should avoid the Disposable Sentry upgrade - it has very little firepower, and is terrible for blocking things.

'We need a medic" - general Two Shitties playerbase
"we need medic 4 duh healz" - general noobs

Despite what most the [casual] players of Two Cities and other noobs will try to tell you, you actually do not need a Medic. Back in the early days of MvM, before there were refunds, and before Medic had the capability to revive or the shield upgrade, playing the Medic class was generally frowned upon, and players preferred to have an extra damage class instead, especially in Gear Grinder. Medic wasn't needed back in the days of Steel Trap, Oil Spill, Gear Grinder, and even in Mecha Engine, and he certainly isn't a necessity now. I once even encountered a squeaker whose response to me telling them Medic wasn't needed was "r u retarded its expert of course you need a medic." No, you do not need one, even in expert; I've done 50 expert tours without one, and our teams have done just fine without.

But does this mean Medic is bad/useless? Certainly not. Medic is just as viable as any of the other classes, but will require more skill outside of Two Cities to play the class effectively, given that with him, the team will suffer a severe drop in sustained DPS without an extra damage class. To make up for the lack of an extra damage class, the Medic can help the team play more aggressively, making full use of the extra damage ramp-up from playing closer to the bots. Medic can also use his various Ubers to help increase damage output, for example, using the Kritzkrieg uber on a max damage Pyro to take out tanks faster or on Soldier to clear out large groups of robots quickly, or use stock uber/Uber Canteens with Canteen Specialist to help a Pyro charge into large groups and clear them out. Running an Ubersaw and using it on weak stray bots and Sentry Busters is also advised to deploy as many ubers as possible. Before playing Medic, it is highly advised that you play the other classes first, so you will better understand which class to support at which point.

Learn when to revive and when to not. If Demo/Sniper is dead and there are Uber Medics, prioritize them; if a teammate died in a large horde of bots that is still nearby, consider not reviving them, as it may end with both of you dead. Also, be sure to get the shield upgrade, as you can block a lot of incoming damage using it (does not stop Pyro flames).

Preferred loadout:

Stock/Overdose
Kritzkrieg
Ubersaw

Any medigun will do, as Canteen Specialist exists along with Crit Canteens (and the canteen effect will last on the patient, even if you stop healing them, which allows for some interesting gameplay, like critting pyro and pulling out your primary on tanks, or ubering a patient and going for Ubersaw hits). However, Kritzkrieg is the best as it will generally help make up for that missing damage from an extra damage class, especially with Ubersaw. Ubersaw is practically a must have for Medic; using it will save you money on Ubercharge Rate upgrades, and will help you deploy more ubers than if you played more passively. Learn which bots you can get easy saws on, like distracted, milked giants that your teammates can already handle alone fairly well.

Common misconceptions:

"Medic is needed" - no. Just no.

"Heavy needs a Medic to do well" - already addressed. And besides, a Medic that does nothing but heal Heavy the entire game is practically useless and a waste of a class slot.

"Medic needs Kritzkrieg" - Quickfix has faster healing and charges shields faster, Vaccinator practically gets 4 quick revives and stops crit damage of the resistance type the medigun is currently set to. Also, Canteen Specialist, as mentioned, is a thing.

"sniper iz uzeless" - Two Shitties noobs, general noobs

Sniper is far from useless. In fact, Sniper is borderline OP in MvM, all due to one upgrade - Explosive Headshot. With Explosive Headshot, any headshots the Sniper lands will cause an effect that damages up to 12 surrounding bots (and spectators, and players - see post here) based on the upgrade level; one tick will do 150 damage, two will do 170, and three will do 190. With this upgrade, Sniper effectively goes from being a single target class to a crowd control class, and an effective one at that, as he can stand far from the front line, behind the team, and like Demo, won't have to focus much on resistances (aside from crit resistance when necessary to avoid having stray crit rockets killing you and such). Like Demo, Sniper will need to focus on clearing out any Uber Meds, made possible with Explosive Headshot, of course. In most cases, the Sniper will be able to simply headshot the patient and the "explosion" will kill any meds on them. As well as doing damage, any kills from the headshot itself and from Explosive Headshot will automatically collect money from the bots, leaving red piles of cash that will still give Scout overheal, making Sniper capable of dealing with bots away from the team without making the Scout's job collecting money any harder, and in general makes Scout's job easier (messing up and getting a bodyshot kill will still drop green money that needs to be collected, though).
***Currently, Sniper kills auto-collect money, even on bodyshots, but Valve has not listed the change in any of the patch notes, so I am working on the assumption that it is a bug that will be fixed***

Keep in mind, there are cases where it would be better to go upradeless Demo than Sniper; when a giant has a very large group of Medics on it, like on Metro Malice wave one, or Cataclysm wave two. Sniper will risk popping a few meds with larger groups of medics with the range of Explosive Headshot combined with the 12 target cap.

Preferred Loadout:

Anything that isn't Huntsman, Classic, or Sydney Sleeper
Jarate/Cozy Camper
Bushwacka

Hitman's Heatmaker is regarded as the best of the sniper rifles, as with its feature, Focus, while active, you won't have to rescope after each shot, and continuously fire while scoped, making it easier to make consecutive headshots; the other rifles are also perfectly viable, however. The Sydney Sleeper can actually still benefit from Explosive Headshot, despite not being capable of headshotting; on "headshots," along with doing area damage, it will apply Jarate to the bots in range - it will lower your single target DPS, but that is generally what you run Heavy for, and it will make Heavy able to put out more damage, anyway. Huntsman is usable, but the damage it is capable will never compare to the damage output you can achieve with a rifle. The Classic is just terrible, as you will need to have full charge to headshot, reducing the frequency of headshotting, and Explosive Headshot damage is not affected by charge on the rifle.

Common misconceptions:

"sniper iz uzelezz" - quite the opposite.

"Sniper needs to be incredibly good to be useful" - it doesn't take a very good Sniper to contribute a lot. You can miss more than half your shots and still put out a lot of damage. Also, generally, your highest priority targets will be easier targets like Heavy robots and giants (especially when there are small bots around the giants, and giants may have Uber Medics on them).

"We don't need more than one Sniper" - I've played Mannslaughter, considered the hardest official mission, with four Snipers. It is not always a good idea, but it is stronger than most players give it credit for.

"Sniper is useless!"

"spy iz uzelezz" - Two Shitties noob

Part of the reason Spy is seen as bad stems from the fact that Spy will take more skill than any class to play effectively from start to finish, thus the class has garnered a bad reputation from the players that play the class. Spy makes a decent money collector as he can run around while disguised and pick up money without taking fire from the robots, but unlike scout, he doesn't benefit from the large collection radius and overheal from money that Scout has. But unlike Scout, Spy can slip behind large hordes and walk past sentries without any problem. If there's a lot of money somewhere and there is also a huge horde of crit Heavies, if scout tries to go for the money, the Heavies will rev up, and pin the Scout to the skybox with their bullets and quickly eat away at his health if he has overheal, and if not overhealed, the bullets will rip Scout apart like a piece of paper; Spy on the other hand will be able to walk in disguised and pick up the money uninterrupted. Unlike Scout, however, Spy won't have the same insane move speed as Scout, so you will need to invest in Movement Speed as soon as possible and be more aware of where money is. In addition, Spy is one of the cheapest classes to maximize efficiency.

Spy is also good at crippling giants. At max Armor Penetration, Spy will do 938 damage a stab to a normal giant. With max Swing Speed and Penetration, a Spy can get in 2-4 stabs in on a giant (you will usually get more on a distracted giant than on one that doesn't have any other players in its field-of-view), taking between 1876 and 3752 health from the giant; in addition, since the giant turns to focus on the Spy, the other team members will have time to finish off the giant while Spy is holding the bot aggro. Unlike other giants, Giant Medics will not turn around when you stab them, meaning you can get in enough stabs on one to kill it, but be wary, as its patient will turn around to attack you, so you will likely need to use the Dead Ringer to get out if you can't tank the damage.

Preferred loadout:

Diamondback/L'Etranger
Sapper doesn't matter
Stock/Big Earner
Dead Ringer

As a Spy, you will want to avoid using your pistol as much as possible, but the L'Etranger can help you get your cloak back up if needed, and the Diamondback can be useful for putting in a little extra tank damage with the crits earned from stabs, or pick off that Sniper that's harassing the team from a distance instead of spending time walking over to it. If you won't be worrying too much about taking a lot of damage, the Big Earner helps you get back to stabbing earlier as it will fill up cloak on kills; if survivability is more of an issue, go with stock, as it is a better choice in cases like dealing with Giant Medics (the patient will most times turn around and attack you by the time you kill off the Giant Medic, so you may need more health to tank it, even with Dead Ringer it will sometimes be a problem). Definitely avoid the Your Eternal Reward at all costs; as a Spy, you will want to be focusing more on damaging giants, and not being able to disguise before attacking a giant just causes more trouble for you than it's worth. Kunai is usable, but is ill-advised for less skilled Spies.

Spy will practically need to run the Dead Ringer, as the robots will continue to attack you, even for a while after you cloak, and the 50% damage resistance from the initial hit, and 20-65% while Dead Ringer is active helps a lot, as well as the increased move speed it gives after feigning death. While the other watches are usable, they will be much harder to play with, and are not recommended for beginner Spies.

Also, keep in mind that any disguise will fool robots, but you should disguise as a class that is equal in speed to Spy, or faster (I usually just disguise as a Scout).

Common misconceptions:

"Spy should upgrade sapper" - sapper upgrades are not nearly as important as knife upgrades. You should prioritize Movement Speed and knife upgrades before touching sapper. In some cases it is advisable to put a tick or two into sapper early, but generally should be avoided.

The Spy's sapper IS NOT CROWD CONTROL, all you are doing is stunning bots temporarily - they're not dead, they are still there, and they will reactivate. The Demo/Sniper that you will have on your team, about 99% of the teams you play with, should be able to clear out the large, dangerous robot hordes that people think sapper is oh so great for dealing with - the Demo won't have any problem dealing with these hordes anyway if he isn't completely braindead and realizes his traps that are just as effective at medic picking can also thin out large hordes, and sapping bots messes with the hitboxes making it harder for Sniper to clear them out with Explosive Headshot. Leave the "crowd control" to the crowd controllers, and do your job of focusing on large damage to giants, drawing aggro from the team, and collecting money.

And in addition to Sapper Power upgrades being low priority, sapping giants only gives you less time to backstab, as they will aggro you sooner. The sapper does not stop Giant Medics from ubering, and it only makes their patient attack you sooner, making it harder to kill the Medic. Never sap and stab - always stab first.

"Spy iz uzelezz!"

Operation Oil Spill takes place on three maps: Decoy, Coaltown, and Mannworks. Decoy and Mannworks are tighter and more compact, while Coaltown is longer and has a longer starting stretch. There are two missions on each map for this tour.

I have screenshots of recommended Engineer setup locations for each map, but do take note that you don't absolutely have to build in these exact spots; however, they are generally very solid setups you should use if you aren't experienced and don't want to run the risk of building in a spot that makes you deadweight to the team.

Engineer setups:

It's best to have the teleporter entrance in the middle so that it takes both sides equal time to get to it.

And you will generally want the exit on top of the center building turned facing to the left

If the bots are going left (the sentry will block Giant Scouts fairly well here)

If pushed back on the far left (this sentry spot will block Giants)

If pushed back middle left


Defending spawn from the left side

If the bots are going right (this sentry spot is somewhat good at blocking Giant Scouts, but with a Heavy or two to the left of it)

This spot will block Giant Scouts

And if you are pushed back a bit you can put dispenser there, too

Defending spawn on the right

Now, for more aggressive teams, or when dealing with tanks, it is better to have your stuff up closer to the bot dropoff area. It is not advised to place buildings here when there are Uber Medics, however. (The dispenser can go on either side)

And if your team is extra ballsy, this spot will also do fairly well at blocking Giant Scouts

Another spot you can put sentry is up here. If there are no Giant Scouts to block, and you have bots spawning up top as well, you can place it here to deal with them, especially Snipers, since support Snipers will spawn up here. It also gives the sentry a view of the main bot path.

Engineer setups:

Like Decoy, you're going to want to have the teleporter entrance in the middle so that both sides can access it as quickly as the other.

The best place for the exit is on top of the center building facing whichever direction the bot path is.

And on waves with Spies, if you have a Sniper standing up on the sign, it's best to move the exit back some so the Spies can't jump up to stab the Sniper.

If the bots are going left (okay sentry spot for blocking Giant Scouts)

This is a better sentry spot for blocking Giant Scouts

If the bots go to the far left and you are pushed back (this sentry spot will block Giant Scouts completely)

You can also put the dispenser here

You won't really need to use it since the previous one works, even if the bomb is behind it, but this spot will also block Giant Scouts

As well as here

Spawn defense for bots coming in on the left side (sentry will block Giant Scouts here)

The dispenser is safer if the bots take the inner right path

If the bots go to the right (an okay spot for blocking Giant Scouts)

If pushed back when the bots go on the inner right path (this spot will block Giant Scouts)

If bots take the outer right path (this spot will block Giant Scouts)

A little further back (also blocks Giant Scouts)

Spawn defense for the right side (this sentry spot will block Giant Scouts, and having the dispenser there will provide ammo to teammates on the ramp)

Another, less aggressive dispenser spot

If you are playing with more aggressive teammates, or are dealing with tanks, this is a good setup (not advised when dealing with Uber Medics)

Another setup with a safer dispenser location


Bomb reset locations:

There are two places on this map where a Pyro, Force-A-Nature Scout, or anything with reliable knockback can completely remove the bomb from the map until the next bot spawns in by knocking the bomb carrier into a pit. There is a large pit behind the center building a short walk from spawn.

Not too far from that one on the left side, there is another pit.

Engineer setups:

Like the other two maps, you'll want the teleporter entrance in the middle of the two spawn doors.

You can put the exit in the building in the middle for either bot path

If they're going left, you can also put it here

If right, here

If the bots take the left path

This is a little better for blocking Giant Scouts, but you will still want to have a heavy or two next to it

If pushed back a bit (this sentry spot is good for blocking Giant Scouts)

If the bots take the left path, they will go to the right side at the middle of the map, and you can use this spot when pushed back (it will also work okay when pushed back on the right side)

Defending spawn on the left side

If the bots take the right path

If you have a Sniper standing up on the crates behind the team, this dispenser spot is also okay, and the Sniper will get ammo from it there

This is a better sentry spot when there are Giant Scouts

And if pushed slighty back, the dispenser can be placed here

Since the bots will go to the left side at the middle of the map when taking the right path, this is a good spot to set up

Spawn defense on the right side

For more aggressive players, this is a good spot, and the sentry will block Giant Scouts (not advised when dealing with Uber Medics)

This is a good dispenser spot if you don't have too many giants, or the team is doing well at keeping them from advancing

Nope, those melee bots won't be able to hit it here

More aggressive setup for the right side

The dispenser can also go on this side (and helps if you have a Sniper standing up on that rock)

My personal favorite sentry spot. Makes Sentry Busters blow where they spawn instead of running to the sentry, and melee bots can't get to it and just stand and stare at it

In Operation Oil Spill, there are six missions - two for each of the three maps.

Each mission will start you out with $400. This isn't enough for some classes to play very effectively, and generally in the more difficult tours (aside from Mecha Engine, which drowns you in money from the get-go, and Two Cities which will give you a decent amount of starting money) an upgradeless Heavy or Demo will be used in place of these classes for the first couple waves. However, Oil Spill missions are easy enough that you shouldn't really need to use this strategy, and in some cases will allow for harder starting classes to play more effectively early on.

With $400, you starting upgrades should generally be as follows:

Scout - 2 Movement Speed (Coaltown, usually) or 2 Jump Height and 1 Movement Speed (Decoy and Mannworks, usually)

Soldier - 1 Reload Speed or 2 Firing Speed

Pyro* - 1 Damage or 1 Movement Speed and 1 Health on Kill

Demo - 1 Reload Speed

Heavy - 1 Firing Speed or 1 Penetration (it is better to have it if you have a lot of bots that bunch up together, otherwise go with Firing Speed - I pretty much only get Penetration as my first wave upgrade on Mannslaughter)

Engineer - 3 Dispenser Range and 2 Building Upgrade Canteens (pretty much the only way you should upgrade first wave with $400)

Medic - 1 Projectile Shield

Sniper - 1 Explosive Headshot

Spy - 2 Movement Speed

*It is generally accepted in Expert for Pyro to get 4 Airblast Power first wave. I am not a huge supporter of this, as, generally, you shouldn't need that much Airblast Power to push smaller bots back a decent amount or to even pit them, and giants will take too much ammo for you to really push them anywhere. Besides, good teams won't be relying on bomb resets, or have too many ubered bots swarming them.

Also, keep in mind that you can unupgrade anything you already upgraded before wave one starts, and at anytime during wave one. Once you pass wave one, you will need to have a refund to fix any mistakes/bad upgrades you make.

Recommended class setup:

Scout/Spy
Engineer
Heavy
Demo/Soldier/Sniper
Optional (crowd control recommended)
Optional (tankbuster recommended)

Wave 1

Max Credits by start of the wave: $400
Max Credits received from the wave: $900

Subwave 1: Scout x64
Subwave 2: Giant Soldier x1, Pyro x12

For the first subwave, Soldier, Pyro, and Engineer's sentry will be the strongest, as they will deal with Scout robots the best. For the second subwave, you will want to have a Sniper, Soldier, and/or Demo dealing with the Pyros early, while the Heavy focuses the Giant Soldier (it helps to have a Scout milk it).

Wave 2

Max Credits by start of the wave: $1300
Max Credits received from the wave: $925

Subwave 1: Tank x1, Demoman x25
Subwave 2: Heavyweapons x20
Subwave 3: Giant Scout x1

The tank will come first, so the team may want to focus all damage on the tanks until the Demos start dropping. A crowd control class should stop attacking the tank shortly to clear out the first 5 Demos that drop, and get back on the tank shortly after. If upgraded properly, the team should be able to take down the tank before the next wave of Demos come. For the second subwave, a Demo/Sniper should focus on clearing out the Heavies when they drop to make it easy for the rest of the team to clean up the survivors. Towards the end, a Giant Scout will drop down, and you will want to have the sentry and Heavy in a spot where they can bodyblock it.

Wave 3

Max Credits by start of the wave: $2225
Max Credits received from the wave: $1100

Subwave 1: Sandman Scout x6, Huntsman Sniper x24
Subwave 2: Soldier x38
Subwave 3: Pyro x8, Huntsman Sniper x 32
Support: Spy x2

Wave 4

Max Credits by start of the wave: $3325
Max Credits received from the wave: $700

Subwave 1: Fist of Steel Heavy x1, Pyro Pusher x7, Extended Backup Soldier x1, Demoknight x24
Subwave 2: Giant Charged Soldier x1, Pyro Pusher x7, Extended Backup Soldier x1, Demoknight x24
Subwave 3: Giant Heater Heavy x1, Pyro Pusher x7, Extended Backup Soldier x1

Wave 5

Max Credits by start of the wave: $4025
Max Credits received from the wave: $1100

Subwave 1A: Giant Rapid Fire Soldier x2, Pyro x15, Quick-Fix Medic x4
Subwave 1B: Soldier x20, Quick-Fix Medic x 20
Subwave 2: Scout x30, Sandman Scout x10
Support: Sniper x1

Wave 6

Max Credits by start of the wave: $5125
Max Credits received from the wave: $850

Subwave 1: Scout x55, Heavyweapons x10, Demoman x16
Subwave 2: Heavyweapons x12
Support: Sniper x2, Spy x4

Wave 7

Max Credits by start of the wave: $5975
Max Credits received from the wave: $1100

Tank x2, Gloves of Running Urgently Heavy x 5, Heavyweapons x8, Giant Heavyweapons x2, Quick-Fix Medic x8
Support: Spy x2, Scout (melee) x3

Max Total Credits from the mission: $7075

Waves: 6

Recommended Class Setup:

Scout
Engineer
Heavy
Soldier/Demo/Sniper
Optional (Tankbuster recommended)
Optional (Crowd Control recommended)

Wave 1

Max Credits by the start of the wave: $400
Max Credits received from the wave: $700

Subwave 1: Demoknight x18, Huntsman Sniper x24
Subwave 2: Giant Demoknight x1, Quick-Fix Medic x4, Huntsman Sniper x3
Subwave 3: Giant Demoman x1, Quick-Fix Medic x1, Huntsman Sniper x3

Wave 2

Max Credits by the start of the wave: $1100
Max Credits received from the wave: $700

Subwave 1: Tank x1
Support: Gloves of Running Urgently Heavy

Put your classes with the highest tank DPS on the tank, and leave the support bots to the Engineer's sentry. With enough focus on the tank, it should be destroyed fast enough that bots dropping the bomb shouldn't be a concern, especially with the Engy keeping them from advancing as quickly.

Wave 3

Max Credits by the start of the wave: $1800
Max Credits received from the wave: $700

Subwave 1: Giant Rapid Fire Soldier x3, Extended Concheror Soldier x9, Demoknight x9, Quick-Fix Medic x9
Support: Spy

Banner Soldiers can be quite tricky to deal earlier on. The best way to handle these, as there aren't that many of them out at once, is for a Demo or Sniper to focus on clearing out the crowds that come with the Giants, with a carpet of stickies, or Explosive Headshot. Once the crowds are cleared, a Heavy should be able to handle the Giant Soldiers without too much problem with at least one Destroy Projectiles upgrade. Scout milking and marking the giant helps, or a Spy could put a fair amount of damage on the giants to help the Heavy finish them off faster. Be sure to be careful of Spies when they spawn in; not too many spawn at once, so the Engineer shouldn't have too much trouble with them, but it is still helpful to assist him.

Wave 4

Max Credits by the start of the wave: $2500
Max Credits received from the wave: $900

Subwave 1: Giant Pyro x5, Super Scout x10

Switch the class composition to 4 Heavies, a money collector, and an Engineer. The Heavies won't even need to upgrade to handle this. The Engineer should put the sentry in a spot that blocks the Giant Scouts, and put the dispenser forward for the Heavies to deal with the giants. This wave should not require any more explanation. Well, while you don't really need to do this, the entire focus of this wave is single target damage - it is purely a DPS check, hence why I am suggesting stacking Heavies

Although, alternatively, if you happen to be running a Spy, by this point the Spy should be able to heavily cripple the Giant Pyros, making them short work for the Heavies.

Wave 5

Max Credits by the start of the wave: $3400
Max Credits received from the wave: $1300

Subwave 1: Scout x24, Sandman Scout x20
Subwave 2: Heavyweapons x16, Scout x20, Sandman Scout x20
Subwave 3: Scout x9, Sandman Scout x9

For the Scout subwaves, the Engineer's sentry should have very little trouble clearing them out; crowd control classes will help to clear them out faster. Crowd control classes will be very effective during the Heavy subwave as well, especially a Demo or Sniper. Overall, this is a very straightforward wave - put out damage, kill bots.

Wave 6

Max Credits by the start of the wave: $4700
Max Credits received from the wave: $800

Subwave 1: Fists of Steel Heavy x13, GRU Heavy x12, Heavyweapons x12
Subwave 2: Tank x2, GRU Heavy x28, Fists of Steel Heavy x4, Extended Concheror Soldier x12

With a large portion of the bots being melee bots, combined with the tank, this wave is mostly just a DPS check; put out damage with the classes most suited to the target. Tanks won't come until after the first subwave is finished. By this point, the crowd controllers should have little problem dealing with the Heavies that drop, and a Heavy will be best suited for dealing with the Fists of Steels. In the second subwave, you will want to have a Demo or Sniper trying to clear out as many of the Concheror soldiers they can as early as possible to mitigate the threat they pose.

Max Total Credits from the mission: $5500

Waves: 6

Recommended setup:

Scout/Spy
Engineer
Heavy
Demo/Sniper
Soldier/Pyro
Optional

Wave 1

Max credits by the start of the wave: $400
Max credits received from the wave: $700

Subwave 1: Scout x24, Sandman Scout x20
Subwave 2: Heavy x20, Sandman Scout x16, Scout x8

Wave 2

Max credits by the start of the wave: $1100
Max credits received from the wave: $900

Subwave 1: Huntsman Sniper x24
Subwave 2: Tank x1, Sandman Scout x20, Giant Demoknight x3, Quick-Fix Medic x3, Huntsman Sniper x9

Wave 3

Max credits by the start of the wave: $2000
Max credits received from the wave: $800

Subwave 1: Extended Concheror Soldier x24, Quick-Fix Medic x24
Subwave 2: Giant Rapid Fire Soldier x2, Extended Concheror Soldier x4
Support: Sniper x2

The dreaded, infamous Cave-In Wave 3. Before buffs to the Quick-Fix and the Concheror, this wave could have been considered intermediate, but this wave is definitely advanced difficulty now. This wave will stand between you and your tour completion if you are not prepared.

While the Medics may not me Uber Medics, you will have a very hard time killing their patient without high burst damage, especially coupled with the fact that the Soldiers will heal every time they hit you. You will basically want to treat the Medics as if they had Uber, and have a Demo or Sniper try to clear out as many as possible when they drop.

Wave 4

Max credits by the start of the wave: $2800
Max credits received from the wave: $800

Subwave 1: Tank x3, Sandman Scout x40, Scout x40

Wave 5

Max credits by the start of the wave: $3600
Max credits received from the wave: $1100

Subwave 1: K.G.B. Heavy x20, Uber Medic x20
Subwave 2: G.R.U. Heavy x12, Uber Medic x12
Subwave 3: Sandman Scout x18
Subwave 4: Sandman Scout x12, G.R.U. Heavy x4, Uber Medic x4

Wave 6

Max credits by the start of the wave: $4700
Max credits received from the wave: $1300

Subwave 1: Giant Flare Pyro x4, Heavy x8, Pyro x8, G.R.U. Heavy x36, K.G.B. Heavy x44
Subwave 2: Tank x2
Subwave 3: Giant Rapid Fire Soldier x2, Heavy x4, Pyro x4, Giant Flare Pyro x2, Quick-Fix Medic x2, Flare Pyro x12

Max credits received from the mission: $6000