You've just booted up dirty bomb, you've picked a game mode, and you've loaded into a match. You're ready to go, to sink your teeth in and play dirty with the best of them. But as you play, you look in the game chat. you see the same thing over and over again. "Ammo!" or "Medic!" repeated verbatim, over and over again. Occasionally, you'll see your name, and someone asking for ammo or health. You dont know what theyre talking about, so you just keep going about your business, dying. Then, having been told that you lost, you start to wonder where it all went wrong.
Well, the answer is simple. It isnt necessarily that the enemy team out gunned you or that they used cheap tactics. The biggest factor in your failure was not knowing what you were there for. Ask yourself some questions: What merc were you playing as? What abilities do they have? What exactly do those abilities do? If you can't answer any of those questions, then read on and be educated. I'll go over what various roles each merc fits into and what you can do to maximize your performance, and hopefully make life less difficult for your teammates.

If you're new to the game, the concept of unique mercs is probably a more familiar concept than you think. If you've ever played other class based shooters, such as Team Fortress 2, Planetside 2, or Battlefield, then you already have a basic understanding of class distinction. For those of you used to shallower titles such as Call of Duty or Counter Strike, I'll fill you in on what exactly is going on.
Classes are a way to divide the labor of teamwork among specialists on your team. In Dirty Bomb, there are four classes: Engineers, Medics, Slayers, and Supports. More detailed information on each class will be provided in the body of this guide.
Mercs in Dirty Bomb are subsets of the classes you are familiar with. Each merc fits into a general class, but fulfills the requirements in slightly different ways. Some mercs might be more suited for hugging teammates to provide help, while others might benefit from being farther away. That is only one and a very general example, but it is one way mercs can be differentiated. Again, the mercs themselves will be described in their respective class sections. If you've read this far, then you are prepared to read on and learn each of the classes.

In each section, I will describe what exactly defines a certain class, which mercs fall into that category, and tactics and strategies you should be using in game.

The definition of an engineer is a straightforward one. It is any merc that has the ability "Objective Specialist", which allows you to arm and disarm C4, and repair EVs and generators much faster than normal.
Now engineers are by no means defensless. At a glance, they could be mistaken for lite slayers. Proxy is a glass cannon armed with shotguns, speed, and her infamous proximity mines. Fletcher also can equip shotguns, although in practice his primary will be his sticky bombs. Bushwhacker is armed with the some of the most potent SMGs, and a well placed turret is great area denial.
Don't let yourself get distracted however. You are not there to kill people. An engineer's sole reason for existing is to take advantage of objective specialist. If you see somebody who was downed, ignore them. If you have to go to work, ignore it. If your house is on fire, move your computer to a different house and keep playing. Whatever you do, do not take you eyes off of the objective.
That sounds quite extreme but it is only half a joke. New-ish objective players tend to get distracted by going for kills or trying to revive teammates. When this happens, the objective doesnt get planted and precious time is lost waiting for them to finish something they shouldnt have been doing in the first place. So how do you avoid doing this yourself? They key is to trust that your teammates will take care of killing and reviving, the jobs theyre equipped to do, while you do the voodoo that you do so well.
This goes for when you are trying to plant/repair/defuse an objective. When you have done this already, feel free to break out those OP mines and stickies and defend it to your dying breath. Keep in mind that you're not quite as powerful as a dedicated slayer, so you'll be relying a lot on your medics and supports to keep both you and your slayers alive.
One final note is that you will die, A LOT. Objective players focus on the objective, and sometimes that means getting last second plants or defuses while being shot at. If you're attacking, the enemy's job is to defend the objective, so dont be surprised if they prioritze killing you over your other teammates. This is something you'll have to take on the nose and fight through, although a good medic can help reduce the number of times you'll need to run back from your spawn. Though by no means garuanteed, dont be surprised if you end some games with a negative KDR. It's all part of the job you signed up for, and your teammates will appreciate it.

This is perhaps the easiest class to understand, and the one new players gravitate towards the most. This does not mean it is the easiest role to fill, far from it. A slayer is a character who's only reason for existing is to kill people. They dont do objectives, they don't keep their teammates supplied with anything, there is only kills.
While this might sound like an easy concept to wrap your head around, you are correct. This is the reason most new players go for it. The miscalculation they make is that in order to be a slayer who contributes to the team, you need to be the best there is at killing people. Your abilities can boost your effectiveness, but not nearly enough to make up for a plain lack of skill or knowledge.
But this is an objective based game, you might say. How does killing people constitute PTFOing? Well, think of it this way. The enemy team can't do anything if they're dead. The longer they're dead, the less they can do to stop the rest of the team planting or defusing or general PTFOing. Where this misconcpetion comes from is when a team stacks slayers, and is then surprised when they get pounded into the dirt. Which brings us to a cautionary point about slayers.
You are not a one man army. Slayers are good at killing people, the best in fact. This does not make them indestructable or perpetual. They need health and ammo just like anyone else, so for every slayer on your team, make sure there is at least one medic, and one support for every 2 slayers to give them ammo.
Remember, a slayer's job is to get a good KDR, to kill much more than they are killed. 2 KDR is a good benchmark for an effective slayer. Having effective slayers is also a good indicator of a well balanced and coordinated team. It means the medics are healing and the supports are supporting. If you are playing a support or especially medic, you can use a slayers score to gauge your own performance.

Author's note: I'd like to address a few comments left by readers about the so called "Recon" class. A Recon merc, as it has been described to me, is a merc that specializes in finding specific targets and taking them out one at a time, as opposed to crowd control mercs such as Nader or Fragger. In this context, Recon does not differentiate itself enough from other slayers to justify its own class, and here's why. Neither class does anything but kill people. Redeye and Vassili have abilities for spotting (why Phantom is grouped as a Recon I'll never know), but it's still just a means to an end, killing. Whether you are killing one person super dead or many people at once, the end result is dead enemies, the definition of a slayer.

GIVE AMMO
Supports are the other class new players tend to gravitate towards when first starting to play GIVE AMMO. On paper, this makes sense. Support mercs have good weapons, some would say the best in the game, and in some way or another have fantastic area clearing or area denial abilities GIVE AMMO. So why is it that people always seem to disparage people who play these classes? Why is it that, in game, you always get the most frustrated at them?
You may have gotten some subliminal hints from me as to the reason for this. If not, let me state it a bit more clearly. A lot of players who play support, especially low level players, don't realize that they need to GIVE AMMO ALL THE TIME. If you come from a Call of Duty or Counter Strike background, you may not be used to the problem of running out of bullets. Most of the time you die or the round resets before you run out of ammo, in which case you spawn back in with a full load. Dirty Bomb is different. Take the KEK for example. It does 11 damage per shot, and we'll take Skyhammer as our target, at 120 health. With just body shots, it will take 11 bullets to kill one merc, not counting you misses. Headshots will halve this amount to 6, but with about 35% accuracy, you need almost an entire mag to kill one merc, 2 if you're lucky and accurate. Couple that with the fact that you only start off with 3 magazine worth of ammo, and you're going to find yourself in a bind pretty quickly. There are ammo caches, but they're not always in friendly territory.
There are two solutions to this problem, depending on which ammo giving ability you have. If you are playing as Kira or Stoker, you will have ammo stations. These are functionally identical to med stations, but give ammo instead of health. The best way to use these is to find a med station and plop it down right next to it. A lot of new players don't know to look for ammo stations, but they're drawn like moths to a flame to med stations. If you place your ammo next to the mess, you provide the player with both ammo and health, saving them both a trip to an ammo station and the trouble of having to think about ammo in the first place.
Ammo packs are a little trickier to use to supply a whole team, and require a lot more conscious effort on your part. Ammo packs, used by Skyhammer and Arty, are a consumable that, once picked up, instantly resupply the target with maximum ammo. You can hold onto a maximum of 3 or 4, depending on your loadout's perks. One common strategy employed with ammo packs is to throw them all out at the spawn, and let team mates get on extra mag off of them. This is wasteful on two fronts. One, your teammates will already have enough ammo to start a fight. They don't need any more once they spawn. Two, once you do that, you won't have any ammo to give to people at the front, who probably have expensed their ammo and actually do need more.
The best way to use ammo packs is to look for the ammo symbol above people's heads, much as you would in Battlefield. That symbol means that person is either out of ammo for their primary or will need ammo very soon. Throw ammo at them if possible, or at least in their general area. You can also throw ammo around med stations as you would an ammo station, but keep in mind that you will have to keep putting down ammo packs in this case.
Support is one of the hardest classes in Dirty Bomb to play correctly (more on medics later), but not because anything they do requires a great deal of skill. It's simply because you need to focus on the needs of your team just as much as you do killing the enemy, and this is something that is very easy to lose track of when the bomb is down and everyone is scrambling to defuse. Supports have the edge over medics in that they're better in combat, but their job is no less cognitively intensive.

Finally we get to the class that so many people play so very, very wrong. On the surface, medics dont seem very complicated. They heal the sick and raise the dead. What gets in the way of this is certain non-medical attributes that medics have. First though, we'll cover those two defining attributes of the medical profession. First off, healing the wounded. Unlike supports, which are limited to two ways they can give ammo, each of the 4 medics has a unique healing ability that distiguishes them from the others. They are, in decreasing order of healing power, Aura's med station, Phoenix's healing pulse, Sawbonez's med bags, and Sparks' med packs.
Unlike in the previous sections, I will go over each individual merc's abilities simply because they are much more varied and require more explaination than a sweeping overview can provide. Medics are THE most important class to keeping a team going, so I want you to understand exactly what is at your disposal.

Healing
Aura's med station is one of the most common healing methods you will come across in game. There are two reasons for this. The first is that Aura is one of the default unlocked mercs that everyone owns. The second is that you the Aura in question does not have to think about giving heals to anyone in particular. She just throws it down in ideally a safe area and everyone runs there when they need health. The healing is not instantaneous, but given time you will reach full health.
Phoenix's healing pulse will instantly give a certain amount of health to anyone within the pulse's area of effect, given by a holographic ring surrounding him. The amount of health given depends on how long the pulse is charged for. Tapping Q will give the minimum amount of health, along with a 5 second cooldown. When charged to it's maximum healing potential, the cooldown goes to 10 seconds. You can hold it at this charged state for an additional 10 seconds, but you recieve no additional healing power by doing so and the cooldown rises to 20 seconds if held for the maximum time. Phoenix is also healed by his own pulse, whether or not someone else is inside the radius.
Sawbonez's med bags are a sort of individual med station. They will heal the recipient to maximum health over a certain period of time. However, they will only continue to heal as long as the target doesnt recieve any damage. If the target takes damage of any kind, be it from a fall or a bullet, the healing is stopped and does not resume until hit with another med bag. You can carry 3 or 4 med bags at a time, depending on the perks of your card. Sawbonez can also heal himself with his med bags, however the heal rate is significantly slower than it would otherwise be for teammates.
Sparks' med packs are similar to med bags, however their heal effect is instantaneous and fixed at a certain number. Her's are by far the weakest in terms of healing potential, but this is made up for by her other ability described below.

Reviving
Medics are defined by their ability to instantly revive downed teammates, as well as their ability to heal hurt teammates. What takes any other merc 6 seconds to do, medics accomplish in literally no time. With the exception of Sparks, all medics are equipped with defibrilators. Defibs will instantly get a player back on their feet with a low amount of health. The amount of health a revived player is given can be increased either by equipping the Get Up perk (+30% health), charging the paddles (up to 100 health), or both. In order to use the defibs, you wil need to be right on top of the target. When charging the paddles, you can only move at walking speed. This can be avoided by jumping before charging, in order to maintain your momentum from sprinting.
Sparks' revive ability is unique and quite contriversial. I won't speak to the balance aspect of her ability, as that is beyond the scope of what I am writing, but I will tell you about it so you know how to use it. She is equipped with, no joke, a revive gun. The REVIVR, as it is known in game, is capable of reviving teammates from any distance away as long as Sparks can get line of sight. Note that the REVIVR is only capable of reviving downed teammates, not healing wounded ones. Not only can the REVIVR pick up friendlies, it is also a weapon which can kill enemies. The REVIVR has no spread and unlimited ammo, which is what makes it so divisive. Again, not making any claims about it's balance, just stating it's characteristics.

Now that you know the capabilities of each merc, I'll tell what situations each of them is bult for. Aura is a primarily defensive medic. Med stations are stationary, which makes them great for holding a position, but less so for trying to take one. She also is equipped with short range weapons, primarily shotguns, so her ability to kill is limited to point blank range. When playing as Aura, make sure you stick to the bulk of your team, at least two other people who can do the majority of the combat. Your purpose is to keep them alive, and revive them if they go down. Your kill count is secondary to their lives.
Phoenix and Sawbonez are both primarily offensive medics. Their means of healing are tied to their bodies, so in order to heal their teammates, they must constantly be near them, and that often means being near or in combat. They both have the most effective medic weapons, SMGs such as the Crotzni, so they're at least somewhat effective beyond close range. They are on the low end of the health spectrum though, so don't try to be Fragger. Let Fragger be Fragger, you just give him health.
Sparks is the Long range medic. Thanks to the REVIVR, she doesnt need to be close to the action in order to keep her team afloat. Med packs can be used to heal teammates in need, but this means getting into the the thick of things with your team, so you'll need to be in and out before you take too much damage. Don't forget as well that the REVIVR is also a weapon. You can harrass enemies you see to help your teammates out from afar.

Remember, you are a healer, not a fighter. Your teammates are going to be much better equipped at kill than you are, so leave that messy business to them. What they can't do on their own is regain their health, so that's what you exist for. Also, be generous, but judicious with your revives. Medics don't have a whole ton of health, so trying to run into a hail of bullets to save one guy is, more likely than not, going to result in two dead medics. At the same time, you should always be keeping an eye out for revive indicators where your teammates died, and making the call whether they are revivable or not. If you don't think you are skilled enough to both be a good medic and keep yourself alive with their limited arsenal, that's fine, play to your strengths. Just remember that sometimes you may be the only one with a medic in your squad. Should that happen, and if you've managed to get this far into the guide, hopefully you will have a little more confidence in picking up the paddles.