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