Here is the full list of all 57 Kill to Collect achievements.
Kill an enemy with the last bounce of the laser disc.
Set fire to 3 enemies with one Incendiary Grenade.
Deploy 4 turrets in a fight
Strangle someone to death with the LazerWhip
Have an Artillerist die by his own grenades.
Complete a floor using just x -attack (Dodge is still allowed)
Kill 3 enemies with one Proximity Mine.
Hit 5 or more enemies at once with Kate Katanas Crackdown.
Clear every challenge room in a bounty without dying.
Land 50 consecutive attacks in a row without taking damage.
Land 20 consecutive attacks in a row without taking damage.
Beat a Challenge Room without taking any damage.
Gib one of every enemy in the game.
Kill three enemies in one bull rush.
Kill 4 or more with one rocket using the Rocket Launcher.
Kill 3 enemies with one use of Ironfists ultimate ability.
Blow 3 enemies up with a Grenade.
Kill 8 enemies with one Lazer Cutter.
Kill a Defender with the Handcannon
Complete a Repeatable Challenge
Complete a "One Try" Challenge.
Kill 15 enemies with a Flamethrower.
Hookshot 15 enemies.
Complete the campaign as Kate Katana.
Complete the campaign as Ivan Ironfist.
Complete the campaign as Riot Ray.
Complete the campaign as Shocking Shelly.
Kill an enemy in a factory shredder.
Watch yourself being placed first on a leaderboard.
Kill a Vanguard with a whip
Kill a friend with the Rocketlauncher
Have your turret kill a Bounty Target.
Revive a friend with less than 1sec left on the timer.
Complete a floor ( not tutorial ) in 90s or less.
Complete a (not challenge, not tutorial) bounty in 350s or less.
Complete all chapters of the campaign in any way you like.
Complete the campaign with Kate Katana on Hard difficulty.
Complete the campaign with Shocking Shelly on Hard difficulty.
Complete the campaign with Ivan Ironfist on Hard difficulty.
Complete the campaign with Riot Ray on Hard difficulty.