Here is the full list of all 42 Gunpoint achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Chicken out of telling Katie the truth at the last minute.
Slam Fritz Gessler's office door into him.
Knock Fritz Gessler out of his office window.
Defeat Gessler by rewiring his gun.
Kick Fritz Gessler's office door into him.
Shoot Fritz Gessler.
Intimidate Fritz Gessler into surrendering.
Beat Fritz Gessler to death.
Mock the chief of police at a critical moment.
Get knocked down by an opening door.
Create a custom mission with at least one objective.
Complete a mission that has guards with no violence, witnesses or loud noises.
Help justify my early, not entirely wise choice of game name by holding someone at gunpoint with the Resolver.
Use the Prankspasm to knock out someone who isn't standing near a power socket (outside of the test lab).
Complete a mission faster than I can.
Upgrade your battery capacity to the non-figurative max.
Publish your personalised epilogue.
Complete the game.
Knock Fritz Gessler out with a punch.
Use the Gatecrashers to kick a door through a window.
Use the Gatecrashers to kick a door into a guard.
Use the Gatecrashers to kick a door off its hinges.
Upgrade your Bullfrog Hypertrousers to maximum jump strength.
Free an innocent man at the expense of catching a guilty one.
Complete the police chief's missions without incriminating yourself.
Use the Longshot to make a guard unintentionally shoot another (outside of the test lab).
Jump into an Enforcer to knock him through a window.
Knock a guard out by opening a door into him.
Conceal your presence at the DataSec break-in from Mayfield.
Tell Gessler that Rooke's hired you to betray him.
Use the Hushcracker to jump through a window silently (outside of the test lab).
Use no violence at all on a mission that has guards.
Upgrade your Bullfrog Hypertrousers to pounce instantly.
Voluntarily tell Katie the truth.
Use the Dropshot to land silently from a great height.
Wire an elevator button to trigger something when the elevator arrives.
Use the Crosslink to create an infinite loop that burns itself out.
Leave no living witnesses to your presence on a mission that has guards.
This is an achievement in name only. No-one admires you for punching a guy that many times.
Steal Gessler's technology for Rooke.
Catch a guilty man at the expense of freeing an innocent one.
Notice the story doesn't necessarily gel with the mechanics. Become qualified games journalist.