Here is the full list of all 22 ChromaGun achievements.
Finish Chapter 8.
Finish Chapter 7.
Finish Chapter 6.
Finish Chapter 5.
Finish Chapter 4.
Finish Chapter 3.
Try jumping... and fail.
Try jumping over a Deadly Electrified Maintenance Tile... and fail horribly.
Find the hidden cake we actually have, as opposed to that other game that doesn't have a cake.
Try painting a brown WokerDroid and realize how pointless that was.
Grill a WorkerDroid on a Deadly Electrified Maintenance Tile.
Simply walk onto the Deadly Electrified Maintenance tile in Chamber 3-1.
Finish Chapter 2.
Fire 100 shots.
Mix a color. It's not that hard, really.
Finish Chapter 1.
Get killed by a WorkerDroid.
Open a door by activating a trigger.
Shoot a WorkerDroid.
Grill 100 WorkerDroids on Deadly Maintenance Tiles.
Solve a chamber in chapter 7 without firing a single shot.
Rescue the WorkerDroid in Chamber 5-2.