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