This guide covers every achievement with tips on how to get them.
The four sections in this guide are Bosses, Easy to Get, RNG, and Multiplayer.
I have no plans on doing a video guide unless someone wants to provide one. (You will be credited as a contributor with a link to your youtube video)
If I have made any mistakes tell me in the comments and I will fix whenever I get a chance.
I also have a guide for Industria! Check it out here
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=2618785660

First Section is bosses, Most are fairly easy but some can be a challenge without a decent setup, so I'll try to give a tip. (bosses are in order)
Season 1
Toad Slayer - Kill the Mega Toad Boss
Has a jumping attack that turns into a double jump attack during second phase so dodge roll often
Sludge Cleaner - Kill the Sludge Swine Boss
Very slow boss, pretty easy to take out
Holy Moly - Kill Epix Mole Boss
Goes under ground often and doesn't take damage underground so try to have a high DPS weapon like the Venom or Love Spreader to take him out quicker, second phase has an area of effect attack
Fitless - Kill Body Positive Hamster Boss
Shoots a seed attack in a rotational pattern but a fairly easy boss, first level fighting a miniboss (two of a weaker Swine Boss)
Dewormed - Kill Wormy Cat Boss
One of the easiest bosses in the game, no tip needed
Party Over - Kill DJ Horse Boss
A Mark Gun with either a fast firing gun like the Machine Gun or Lucky Gun will put this boss down quickly, even quicker with a damage boost!
Season 2
Flush the Toilet - Kill Toilet Monkey Boss
An boss that shoots several AoE attacks and jumps at you aswell, A fast firing gun with the lava damage and either item that makes you invincible (Terminator or Taunt) will make extremely quick work of him
From Dusk Till Down - Kill Mad Bat Boss
Probably the hardest boss in the game currently, shoots several projectiles at you including a AoE line attack as well as chases you, in a room full of spikes. I recommend having the Steel Shoes perk to make this fight much easier.
Emotional Killer - Kill Emo Hedgehog Boss
This boss constantly chases you while shooting projectiles but much easier then the Bat boss, He moves in a straight line until he hits a wall so have him move across the room while firing at him with a high damage gun like a Sniper Rifle or Mega Rail Gun
Interregnum - Kill Junk Queen Boss
A boss that spawns smaller minion enemies, Love Spreader should do the trick on this boss and it's minions fairly quickly
Failed Experiment - Kill Lionstein Boss
This boss has a 4-way laser attack so move around him while shooting, I recommend the venom with lava bullets on this boss
Break the Glass - Kill Ass'inGlass Boss
Final boss currently, has an assortment of attacks but stays in place (to my knowledge). However this stage is filled with several minibosses so be ready and only do rooms with weapons or perks.

These achievements are pretty much guaranteed, no RNG here!
Good Student - Complete the Tutorial
First thing you do
Better Safe Than Sorry - Take two weapons in lobby
You can do this instantly from the lobby, just grab any weapon class and drop the weapon by pressing the middle mouse button on Mouse and Keyboard, or Y/Triangle on controller and then grab another classes weapon
Newbie - Do 1 Run
You don't have to complete, you can instantly leave it if you want
Rookie - Do 10 Runs
You can keep restarting the episode you are on to do this, don't even need to move from the starting room
Stubborn - Do 50 Runs
Same as Newbie/Rookie achievements
Marathoner - Do 100 Runs
Keep on restarting or play 100 rounds either one works :)
Free Marketeer - Sell a Weapon In The Shop
Can be any weapon except for the four starter weapons
Uselessness - Destroy 100 Barrels
Barrels are on just about every floor, just walk into or shoot them until you get 100
Rambo - Kill 1000 enemies
Each episode has more rooms so just keep doing the latest episode you have until you get, helps if you choose the rooms with the purple flames because they spawn more enemies
Can't Touch This - Defeat any boss without using dash
Just have high health and fight either of the first 2 bosses without dodging, You can also use the tank class for its taunt ability to avoid all damage for a few seconds
Trapper! - Get Killed by a Trap
As simple as it gets, just stand on a trap until you die (don't kill all enemies in a room or else traps deactivate)
Oniomania - Spend total 10k in shop
Keep buying from shops until you reach, can be done from multiple runs
Survival Instinct - Kill 30 enemies at one health without healing
First room of first episode just have an enemy bring you to half a full heart (1 hit) not one full heart (2 hits) and then go through the episode without picking up any hearts or going to a healing room
Well, that was impressive - Get Killed by a Rat
One of the first enemies you encounter, the rat with the poking stick, just kill all shooting enemies on a floor and let the rat poke you to death
Arms Dealer - Sell 20 weapons in shop
Just go to a weapons floor and then the sell to any shop until you get it
Speedrunner - Complete any level within 5 mins
Easiest with first level, just rush through it
Risk-Taker - Finish run without picking up any weapon, special item or healing heart
Easiest with first level, can do this one with Speedrunner
Flawless Victory - Complete a level without taking damage
You can even go 3 for 3 with Speedrunner and Risk-Taker, I recommend tank for its invincibility item
You know you can switch weapons, right? - Kill any boss using only class weapon
You don't need to use a starter weapon for every other enemy, just the boss, Easy on the first two bosses
MacGyver - Use 10 different specials
Use 10 different items, don't even need to use against enemies

These achievements are pretty much RNG but most of them are easily attained.
Rising Star - Get 1000 Likes On A Level
Easy to get, just don't go to a shop until the final shop, or sell as many weapons as possible
Influencer - Get 3000 Likes On A Level
Same method as Rising Star but I would also do Like Earning Rooms, these are the rooms with the thumbs up
Celebrity - Get 5000 Likes On A Level
Same as other two, if you get a golden gun I recommend saving it until you get to a shop, they normally sell for 5000+
Meat Shield - Get hit 20 times in single run
This one requires a bit of healing which some runs can be RNG, I'd start as a medic and hope for a run with several healing floors and shops and just allow yourself to be hit several times
Pacifist - Clear room without using any weapons or offensive items
This to my knowledge can only be achieved by an RNG sponsor ability that instantly ends a room
Instagram Model - Get max possible points in Social or Fame room
Can be done in the earlier episodes fairly easily, but also works with Pacifist achievement
Shifty - Sell the Golden Gun in shop
RNG to find it, but guaranteed shop at end of episode
Life Beyond the State - Buy the Golden Gun in shop
Not only does the store need to have one, but you'll also need the money to get it, so really can only be done in the last few episodes. Grab as many purple weapons as possible and sell them as well as doing like gaining floors.
Midas Touch - Get 100 Kills With The Golden Gun
A very weak weapon with low chances of finding it in weapon rooms, get as many damage dealing perks as you can, or rapid firing ones
Have A Blast - Kill 3 Enemies with a single mine
I recommend the second to last episode and killing all enemies on a floor except the turkey enemy and let them shoot the little ones out until 3 are spawned then use the floor mine item on them
Fashionista - Get boots and use invisibility special
All RNG :)
Golden Shot - Kill yourself with the Stimpack
Find the stimpack item and then let enemies get you to half a heart, use the stimpack EZ
Thiccc - Have both skin perks at a time
More RNG :|
Anger Management -Get both low health perks active
RNG and then you have to get to a low enough health to activate both perks
Perk Master - Unlock all perks
RNG getting all perks
Weapon Master - Unlock all weapons
RNG getting all weapons
Items Master - Unlock all Items
RNG getting all items

These ones can be done by yourself or with friends on keyboard/controller. There also seems to be guides on how to do online multiplayer but I have not tested these methods.
I Need A Hero - Revive a friend
Simply let one person die and stand over them to revive them
Dead Weight - Die 3 times in a run in coop in a single room
once you revive someone they respawn with only 1 hits worth of HP, so let them get hit several times and just keep reviving
Am I Playing With Bots? - Revive other players more than 5 times in single room
Keep on reviving the same downed player or multiple if you are playing 3-4 person coop
Ninja - Take the new weapon 3 times in a row in the coop mode
Go to 3 weapon rooms in a single episode and dont pick up any weapons on one person while picking up a weapon on the other

Happy Hunting, and thanks for choosing my guide, hope you have a great day!
-Lua