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