Here is the full list of all 57 Kill to Collect achievements.
Complete a (not challenge, not tutorial) bounty in 350s or less.
Blow 3 enemies up with a Grenade.
Complete a floor using just x -attack (Dodge is still allowed)
Clear every challenge room in a bounty without dying.
Kill 15 enemies with a Flamethrower.
Kill an enemy with the last bounce of the laser disc.
Kill 3 enemies with one Proximity Mine.
Strangle someone to death with the LazerWhip
Hit 5 or more enemies at once with Kate Katanas Crackdown.
Revive a friend with less than 1sec left on the timer.
Land 50 consecutive attacks in a row without taking damage.
Beat a Challenge Room without taking any damage.
Land 20 consecutive attacks in a row without taking damage.
Gib one of every enemy in the game.
Deploy 4 turrets in a fight
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.
Kill 8 enemies with one Lazer Cutter.
Kill a Defender with the Handcannon
Set fire to 3 enemies with one Incendiary Grenade.
Complete a Repeatable Challenge
Complete a "One Try" Challenge.
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.
Have an Artillerist die by his own grenades.
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.
Complete a floor ( not tutorial ) in 90s 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.