I wanted to summarise my experience with hunting achievements in this game into a guide. I won't be going over build specifics or anything extremely in depth, as there are guides that do this already. I will reference and credit them where necessary.
I also want to note that I am not taking into account the new Weapon of Choice DLC. Aside from Balance changes and bug fixes, the DLC did not affect the earning of achievements in any meaningful way.

Complete the Section 11 Training

Complete the Tutorial. You should want to do this anyway if you're new.
I'll also note here that you do NOT have to replay the tutorial each time you start a fresh run.

Complete the Death's Head Biker Gang mission

Complete the first mission. No enemy here is difficult to deal with. They're all slightly easier variants of more dangerous enemies in later missions.

The Boss of this mission is a guy who can attack 2 tiles away for heavy damage, and turns towards you if you stand in his compass points (North, South, etc.) He comes with 2 gun guys as support.

Pretty much anything will deal with him well. I recommend stunning / throwing him, or moving him or yourself into the path of the bullets from his gun support.

Encounter and defeat all 3 lieutenants in the Death's Head Biker Gang mission

Lieutenants are mini-bosses, in essence. To find them, look for fights that have the note 'Lieutenant' when you hover over it.

The three lieutenants are as follows:
• A Heavy(can't be thrown) Biker that attacks in a U shape from left to right for high damage, and gives allies small armour boosts.
  
• A Heavy Welder that attacks three tiles in front of him and has alot of regenerating armour.
  
• A Shotgunner who attacks for high damage and in a three by 1 area in front of her.

You need to succesfully complete the fight for it to count. You do not have to encounter them all in one run.

Complete the Insiders mission

Finish the second mission, which is a Prison. Enemies here come with more special abilities. Making use of Voids and positioning cards is what I recommend for an easier time.

The Boss of this area is a Prisoner that Auto-Attacks if you step in front of him, turns towards you, and deals high damage and push. He comes supported by an enemy that ignores block when attacking, and 2 enemies that don't take damage from the front (except for throws / stuns)
His weakness is similar to the previous boss; movement with Attack / Special cards, or cards that attack from 2 or more tiles away. He's also still susceptible to pushes and throws. Most maps that you find him on have a generous void space; if you have the cards for it, pushing him out of bounds is very viable.

Encounter and defeat all 3 lieutenants in The Insiders mission

Same as the previous missions lieutenants in terms of finding them. Remember that you need to finish their fight successfully for it to count.

The three Lieutenants are:
• A Doctor that move / turns closer when you move, occasionally debuffs you by removing combo or momentum, and deals bleed damage.
  
• A Heavy Chef that attacks many times for high total damage, and occasionally heals allies.
  
• A Heavy Bruiser that has a massive healthpool and Counters you attacks for 8 damage and push.

Complete the Jade Staff mission

Complete the third mission. It has Ninjas in Germany! The enemies here are extremely varied and dangerous in ways you might not be prepared for; this is where your runs might start ending if you aren't ready.

The Boss of this mission is a Ninja that deals high damage for 3 tiles in front of him, and has regenerating armour that hurts you for 6 damage when attacking him (so long as he has armour, you take damage). He also comes supported by multiple enemies.

Despite how difficult the boss sounds, there are a few simple ways to beat him.
• The first is to ignore him entirely and attempt to position yourself or him so that he gets hit by enemy attacks.
  
• The second is to abuse Shatter, a card that removes block from the target and does not trigger the damage from attacking his armour.
  
• The third, and by far the funniest and easiest way, is to simply move him near to a Void tile (which there are plenty of, as he's usually fighting on a roof), and push him off. the Killing blow won't hurt you.

Encounter and defeat all 3 lieutenants in the Jade Staff mission

You know the drill.

The Three lieutenants are:
• A Drunken Master, who attacks many times for massive total damage, dodges the first attack you send his way, and occasionally gives himself a damage or armour boost.
  
• A Heavy Enforcer that cannot be hurt by allies, moves when you move, and each hit of an attack buffs his damage.
  
• A Ninja Master, who can teleport to a new positions and can summon a (weak) copy of herself. She also attacks at range, making her very annoying.

Complete the iCompleti mission

Beat the 4th mission. Enemies here really like to counter or turn towards you. This will be where you fail if you don't have cards to counter their attacks / movement.

The Boss here moves aggressively towards you, does high damage, doesn't advance when attacking (meaning he won't move towards you), and he cannot be pushed. He also spawns with 2 Assassins as support, who are even more dangerous, as they counter and have high health pools. Oh, and their's a gun guy too.

This fight is difficult. However, there are still things you can do to make it easier:

• Cards that throw still work on the boss and all enemies.
  
• You can use Tackle to instakill the boss if you tackle him into a Void space.
  
• Grapple is your best friend for moving characters around.
  
• The boss can still take damage from allies.
  
• Dodge stacking is viable.

Encounter and defeat all 3 lieutenants in the i Completi mission

You already know what it is!

The Three Lieutenants are:

• A Rifleman, who can Auto-Attack up to three times, and turns to face you. While he doesn't sound dangerous, getting close to him and surviving is the difficult part. One of the worst enemies.
  
• A Bartender, who always moves away from you, debuffs you, and summons reinforcements. He also cannot take damage from allies.
  
• An Assassin, who deals massive damage up to 2 tiles away and counters within 1 for similar damage, as well as bleed.

Complete a full run (all missions)




Encounter and defeat all 2 lieutenants in the Renegade Agents mission

I'm combining these two as they kind of go hand in hand.
For Mission Accomplished, simple beat all missions up to and including Renegade Agents.
For Double Crossed Out, the two lieutenants spawn through it as well as during the Final Boss.

The final mission works differently to other missions: you are introduced to the boss immediately, and your goal leading up to the final encounter is to deal 45 damage to the boss. This damage is not permanent, unfortunately. In the final encounter, you need to kill the boss and his lieutenants.

The boss is an ex-Agent, and he's not easy to deal with. He has every trick in the book, and he has a few attacks that he rotates through on a pattern that do something different. Note that HE CAN NEVER BE PUSHED.
The pattern goes like this:

1. Deal 25 damage up to 2 tiles away; has 18 block.
   
2. Deal a shockwave that pushes you and his allies away one space, and will turn to face your cardinal direction (eg. if you move far enough left from in front of him, he will turn left). Has 1 dodge and Heavy.
   
3. Summon a minion (either baton guy that takes your momentum or a gun guy that chases you). Counters incoming attacks for 25 damage up to 2 tiles away.
   
4. Deal 8 damage three times. Has 16 block. Will aggressively chase you down.

As for the 2 Lieutenants:

• The first is a Sonic Ninja; he works like a regular ninja, except occaisionaly he will do a sonic attack that gives you a random injury card. This can be game ending. Kill him immediately.
  
• The second is a Heavy Paramilitary; He can't be pushed or downed, has infinite Auto-Attacks, and hits for massive damage.

While this does sound pretty bad, there are still weaknesses to exploit:

• The Boss can be thrown or grappled. (except during his shockwave attack)
  
• All enemies can still be stunned.
  
• The Boss can use shockwave to push enemies into Void spaces in some maps.
  
• The Paramilitary should be respected, but he'll happily attack enemies you put in front of him.
  
• The boss can be tackled off the map, but this is difficult to accomplish.
  
• The boss starts with one Grunt enemy as support; if you kill him, and then stop the boss from spawning more enemies, you only have to kill the boss and one Lieutenant. NOTE: this may be a bug, so don't rely on this.

Win a run using the Balanced, Aggressive, Counter, Slasher, Grappler & Trickster decks

I'm putting these together as they all require the same thing: Win.
Each deck is designed for a specific style of play and excels in dealing with certain enemies while failing against others. Though, the more important thing for a card game is which cards are worth your time, and the general strat you should be playing with.
There are already great guides by other players that go into detail as to what to do and what cards to take, which I will link below:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2417983938
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2686901245
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2664700321
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2728405704
I will add that some of the information above is outdated; check the comments of each guide for some more recent information.

If you want some general tips:

• Keep your deck small.
  
• Card Draw is important. Recall and Redraw are among the best cards for that.
  
• Use the Gym shop to remove cards first, rather than upgrading or buying new ones.
  
• Get your Momentum up at every possible opportunity.

Win a boss fight without taking any damage

Not that difficult. The first boss is the obvious prime target, but you can get lucky with the 2nd or 3rd boss by pushing them out of the map. Only thing to recommend is to take your time and plan your moves.

Win a fight without using any movement cards

Cards are designated as Movement, Special or Attack just under the name of the card.
This sounds difficult, but is easily done with Grappler or Counter deck. Nothing to recommend here, really.

Deal 50 damage in a single hit

You need some setup for this. The achievement specifies a hit, meaning that a multi-hit attacks' total damage is not counted.

My recommendation is to use Steel Self (doubles damage of your next attack) with a card that has high base damage (ex. Uncontrolled Power, One Inch Punch, Stomp, etc.) or a Combo card (ex. Jumping Punch, Combo Finisher, Big Overhand, etc.). You may need to add some extra damage buffs on yourself to achieve 50, but there are many cards that can do this. The issue here is getting everything set up.

Deal 100 damage in a single attack

Unlike Overpower, this one requires a single ATTACK to hit for 100. that means multi hit cards are on the table.
Steel Self is still your friend here. Combine it with a multi hit attack like Punch Kick Combo or a high damage card like Obliterate.
Note that the hits actually need to land; meaning that if a enemy dies before 100 damage is reached, you will not get the achievement.

Win a fight with 1 HP remaining

Can happen naturally, but rarely.
I don't recommend actively going for this in a run you WANT to finish.
My recommendation to focus it? Take the trickster deck into the first mission' first fight. Kill all but one enemy while taking hits from them (without dying, of course), then use Break the Limit WITHOUT killing the last enemy. From there, use movement cards / block cards to dodge his attacks until your down to one health.
Obviously this still takes some planning, but getting enemies to get you to 1 hp EXACTLY is difficult in the early game.

Get 100 enemies killed by other enemies

Just takes time. There are multiple ways to get enemies to kill their friends:

• Move out of the way so that they shoot each other.
  
• Use a card like Redirect or Shimmy to force enemies to attack.
  
• Use push cards to move enemies into the path of others.

Note that the Ninja Enforcer and Completi Bartender cannot be killed by friendlies.

Throw 100 enemies out of the board

Just takes time. If you want to focus this achievement down, I recommend the Grappler deck on the Insiders (2nd) mission. Most of the fights have plenty of Void spaces to push your enemies out of.
Note that even if the enemy is killed by the damage of an attack when you push them out of the board, they are still counted towards this achievement.

Win a fight by throwing ALL enemies into the void

Pretty much the same as what I said for Into The Void; Take the Grappler deck to the Insiders mission and focus on pushing the enemies off.
I will note that sometimes the enemies won't want to position themselves for easy pushing. If this happens, back off from them and they'll likely move where you want them to.

Complete a run without losing an Informant or Ambassador

Informants and Ambassadors show up in fights that are denoted as 'Informant' or 'Protect'.
Informants are enemies that are marked yellow; if they are the last enemy alive, you will get a bonus. They will still attempt to attack you. You need to avoid them.
Ambassador's are allies that don't (normally) do damage and will be focused by enemies. If they die, you do not get a bonus.

For this achievement, you need to play a 'Protect' or 'Informant' mission, complete it successfully, and WIN a run. Losing a run or losing an Informant / Ambassador negates the achievement.

Some tips:

• The informant can still take damage / deal damage to other enemies. Just don't let him die.
  
• The Ambassador can be pushed around, but not thrown or stunned.

Kill an enemy with Pocket Sand

Pocket Sand is a card that Deals 1 damage and stuns through block. This make sit a difficult achievement.
to make this easier, you need to build damage buffs on your character.

Here are some easy ways to do so:

• Increasing Strength Enhancement (+2 damage every 3 turns)
  
• Strength (+2 damage to all attacks)
  
• Palm Strike (combo card that adds + 2 damage next turn)
  
• Pump up (All attacks deal +3 damage till next turn)
  
• Secret Weapon (passive card that increases damage by 2 while in hand)

Of those ways, Increasing Strength is the best, imo. If you get that enhancement, play a fight where you don't kill the last enemy until the turn that pocket sand kills.

Get a 20 combo

This can be easy or difficult. either a fight will last long enough for you to build up to 20, or it won't.
You also only start with 10 combo as your max, so you need to build up your combo max. Look for fights that reward this.

Here's some tips:

• Combo is given for each successful hit; meaning an attack that hits three times gives 3 combo.
  
• 1 Combo is taken each time you move, unless the card states otherwise.
  
• Cards with yellow X's take all your combo when played. Avoid them for this achievement.
  
• Combo Boost & Jolt are cards that make it easier to gather lots of combo.
  
• Combo Captain Enhancement increases your max combo by 5. Very useful.
  
• Bonus Combo Enhancement gives you 6 combo every 5 turns. Also useful.
  
• Special Serum Enhancement makes your combo max infinite, but you lose all your combo if you do not play an attack card in a turn. I don't recommend this one at all.

Hit an enemy with a stun dart in front of the dartboard in the bar

This is down to RNG. The dartboard only appears in the Death's Head Biker (1st) Mission.
You need to get a specific card, Stun Dart. This card can only be used from 2 or more tiles away. It's also not offered by default by any starter deck.

To get Stun Dart early, you have two choices:

1. Start with a Grappler / Trickster deck and hope you get a card reward that has Stun Dart
   
2. Fully complete a run to unlock Deck Draft mode; this allows you to pick out a deck from randomised selections of cards. You can reset the run until you get what you want.

As for the map, you specifically want the Bar map. It can take some finagling to get an enemy where you want them, and still have the ability to use the card. It took me 10+ turns to get an enemy where I wanted them and have Stun Dart in my hand. Patience may be needed.

Complete a Daily Play

Each day has a new randomised run to beat. This consists of a random starting deck (or draft deck), a random Enhancement, and a random modifier.
A Daily Play has one mission, and is usually much more difficult than the normal game. I recommend going for this achievement once you are confident in FiTS' mechanics.
Some Daily Plays are easier than others. Usually any with Momentum boosting Enhancements are easiest.

Win a fight without playing an Attack card

Basically, play a Counter deck. Can easily be finished on the first fight of the first map, since you can still move out of the way of attacks.

Win a run with at least 50 cards in your deck at the end of the run

This relies on you having enough money to buy cards, as it's unlikely you will get into enough fights to get to 50 cards, and you are not guaranteed to get GOOD cards.

I recommend going for lots of money with the Bounty Hunter Enhancement and combing it with the Apprenticeship Enhancement for lots of upgraded cards.

Here's a little exploit to make it easier to get these two:
In an event space (question mark), sometimes you will get the option to gain an enhancement. If you do, DO NOT close the event window. Instead, ALT + F4 to close the game, and reopen it. When you load the game, you will still have the previous enhancement you got, but the event space will still not be used. you can then keep redoing this until you got the enhancements you want.
Note that this only works if you SUCCEED in getting an enhancement the first time. If it fails and you try to do this exploit, you will only lose again.

I recommend picking up lots of Card Draw cards (Redraw, Retain, Ponder, etc.), as a 50 card deck is not gonna give you what you need to win a fight very often.

Win a run with 16 or fewer cards in your deck at the end of the run

There is already a great guide that I followed myself to get this achievement:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2679237998
Fang's guide will also work towards Purity, another achievement. You can also apply the ideas towards other decks, if Trickster is not for you.

To summarise slightly:

• You start with 20 cards. You need to remove at least 4, and replace many more.
  
• Get at least 1 stun card, 1 throw card, and 1 high damage card(no combo finisher).
  
• Get CARD DRAW
  
• Do Optional Objectives in fights, but don't die for it.
  
• go to Every Gym. Skip Clinics unless necessary.

Even following the guide this took me multiple days of attempts. You need to plan your fight moves ahead. Especially for the ex-Agent fight.

Complete a full run on Purist difficulty

Basically, follow the guide by Fang I posted under Specialist.
Purist difficulty is no joke. No rewinds, enemy moves first, and no reset if you lose.
Please devs don't make me play Brutal difficulty I will not survive.

Have £1,000 at any stage in the game

Just don't spend money, and attempt all optional objectives that give money. Some random events can also boost the amount you get as well, though it is a coin toss.

You can use the exploit mentioned under Bag of Tricks to the same effect ;)

Get the Ambassador to kill someone

Probably the hardest achievement.
There are two ways to do this:

• Push the Ambassador into an enemy that results in the enemy dying. Use Broad Shoulders for better effect.
  
• Use Redirect or Taunt on the Ambassador to make him attack. He only deals 2 damage, though.

For both cases, you want to weaken an enemy as low as possible.

Win a run without upgrading any cards

To get this achievement, you cannot upgrade or OWN a upgraded card when you win a run.
This means that any enhancement or event that upgrades cards should be ignored. The Gym can be used to remove cards and buy them, just not upgrade.

Win a run in under an hour

This isn't too bad, actually. Nothing stops you from playing on the lowest difficulty.
Play the game on the highest speed, as ingame time is what matters. Abuse the Grappler or Aggressive deck.

....or.....

If you are confident in your abilities, use Deck Draft to build a deck with throws, stuns, and lots of movement cards (at least half should be movement). Then load directly into the final mission. If you win, this counts as a successful run.
I did the above strategy and won after a gruelling 33 minutes.

Unlock all cards in the compendium
AND
Unlock all cards and help screens in the compendium

These two go hand in hand, and it's grind time!
The compendium lists cards and what they do. They are locked by default, and unlock as you gain levels. Unlocking them, afaik, reveals their info and adds them to Deck Draft / card rewards.
Levels are gained by the points you earn at the end of a run, successful or not.
Help Screens occur when you encounter new mechanics / use new cards. You'll get all of these naturally.
To fully unlock the Compendium, you need 34 Help Screens, and 242 cards.
Since you unlock 6 cards per level, you need to get to Level 30, which is a cumulative 500k points. (you also unlock a super secret card for getting to level 30!)
A full run that I won on the lowest difficulty ended with me getting ~9000 points.

If you want to increase the amount of points you earn (as you earn them for each fight you win in a run), do the following:

• Do as many optional objectives as possible
  
• Complete each fight in as few turns as possible
  
• Play on higher difficulties for a better multiplier.

Congratulations if you've gotten every achievement!