Here is the full list of all 22 Bloodworks achievements.
Install a mod
Survive for at least 2 minutes
Kill 100 enemies
Survive for at least 4 minutes
Survive for at least 6 minutes
Survive for at least 2 minutes with your pistol alone
Kill 30 enemies in succession without missing a single shoot
Split a bullet and kill two enemies with its halves 15 times in a single game
Kill 3 enemies with a single shot of Rail Gun 30 times in a single game
Shrink 10 boss enemies in a single game
Have at least 20 enemies getting burned by Flame Thrower at the same time
Kill 40 enemies by shattering them in a single game
Kill 3 enemies with a single shot of Plasma Gun 20 times in a single game
Feed 30 enemies into a single Black Hole
Burn 10 enemies with a single Phoenix Dive
Kill Nar-Sie
Kill 3 enemies with a single shot of Shotgun 20 times in a single game
Kill 10000 enemies
Survive for 20 seconds while being surrounded by at least 4 enemies
Kill 1000 enemies
Kill 4 enemies with a single rocket 30 times in a single game
Kill at least 30 enemies under 5 seconds