Here is the full list of all 57 Kill to Collect achievements.
Blow 3 enemies up with a Grenade.
Kill 4 or more with one rocket using the Rocket Launcher.
Kill 15 enemies with a Flamethrower.
Complete a floor using just x -attack (Dodge is still allowed)
Hookshot 15 enemies.
Revive a friend with less than 1sec left on the timer.
Kill 3 enemies with one Proximity Mine.
Strangle someone to death with the LazerWhip
Have an Artillerist die by his own grenades.
Kill a Defender with the Handcannon
Hit 5 or more enemies at once with Kate Katanas Crackdown.
Land 20 consecutive attacks in a row without taking damage.
Clear every challenge room in a bounty without dying.
Set fire to 3 enemies with one Incendiary Grenade.
Beat a Challenge Room without taking any damage.
Kill an enemy with the last bounce of the laser disc.
Gib one of every enemy in the game.
Deploy 4 turrets in a fight
Kill three enemies in one bull rush.
Kill 3 enemies with one use of Ironfists ultimate ability.
Kill 8 enemies with one Lazer Cutter.
Land 50 consecutive attacks in a row without taking damage.
Complete a Repeatable Challenge
Complete a "One Try" Challenge.
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.
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.