Here is the full list of all 83 Slime 3K: Rise Against Despot achievements.
Kill 10000 Bees
Unlock all Slime starting setups
Get a level 3 copy of Super Scytherang
Get a level 3 copy of Nuggets of Darkness
Kill 5000 Doc Ocs
Get a level 3 copy of Fiery Horizon
Get a level 3 copy of Obedient Doc
Get a level 3 copy of Tiny Spring
Kill 666 Maniacs
Get a level 3 copy of Supreme Gun
Beat level 10
Get a level 3 copy of Olive Gun
Kill 300 Mantraps
Get a level 3 copy of Fire Beam
Kill 3000 Ballerinas
Beat level 9
Get a level 3 copy of Dark Side
Beat level 8
Beat level 7
Beat level 6
Beat level 5
Get a level 3 copy of Obedient Zombie
Beat level 4
Get a level 3 copy of Needle Shotgun
Get a level 3 copy of Caliperang
Kill 200 Shieldbearers
Get a level 3 copy of Blaster
Kill 1000 Stilt-Walkers
Kill 300 Pain Lovers
Get a level 3 copy of Rocket Launcher
Get a level 3 copy of Shotgun
Get a level 3 copy of Supreme Shotgun
Beat level 3
Get a level 3 copy of Bananarang
Kill 600 Laser Swordsmen
Get a level 3 copy of Money Box
Get a level 3 copy of Watermelon Launcher
Kill 666 Fire Mages
Get a level 3 copy of Flashes
Kill 1 Wheelman
Kill 50 Fridge Men
Get a level 3 copy of Pistol
Get a level 3 copy of Random Nails
Beat level 2
Get a level 3 copy of Scytherang
Get a level 3 copy of Assault Rifle
Kill 2 Watchers
Kill 10 Madmen
Beat level 1
Kill 100000 Newbies
Kill 10 Thornies
Kill 2000 Martial Arts Masters
Kill 999 Black Swordsmen
Kill 300 Bots
Kill 3000 Brains
Kill 6000 Specters
Kill 30000 Tomatoes
Unlock every ability
Unlock every achievement!
Get a level 3 copy of Triangle of Darkness
Get a level 3 copy of Coin Launcher
Get a level 3 copy of Candy Bomb
Get a level 3 copy of Meteorite Satellites
Get a level 3 copy of Homing Loogie
Get a level 3 copy of Disco
Get a level 3 copy of "Heretic's Fork"