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.
Slam Fritz Gessler's office door into him.
Defeat Gessler by rewiring his gun.
Kick Fritz Gessler's office door into him.
Knock Fritz Gessler out of his office window.
Tell Gessler that Rooke's hired you to betray him.
Chicken out of telling Katie the truth at the last minute.
Voluntarily tell Katie the truth.
Notice the story doesn't necessarily gel with the mechanics. Become qualified games journalist.
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 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.
Publish your personalised epilogue.
Shoot Fritz Gessler.
Conceal your presence at the DataSec break-in from Mayfield.
Create a custom mission with at least one objective.
Upgrade your battery capacity to the non-figurative max.
Complete a mission that has guards with no violence, witnesses or loud noises.
Use no violence at all on a mission that has guards.
Complete a mission faster than I can.
Complete the game.
Beat Fritz Gessler to death.
Knock Fritz Gessler out with a punch.
Intimidate Fritz Gessler into surrendering.
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.
Free an innocent man at the expense of catching a guilty one.
Steal Gessler's technology for Rooke.
Jump into an Enforcer to knock him through a window.
Help justify my early, not entirely wise choice of game name by holding someone at gunpoint with the Resolver.
Upgrade your Bullfrog Hypertrousers to pounce instantly.
Use the Hushcracker to jump through a window silently (outside of the test lab).
Get knocked down by an opening door.
Upgrade your Bullfrog Hypertrousers to maximum jump strength.
Leave no living witnesses to your presence on a mission that has guards.
Use the Dropshot to land silently from a great height.
Knock a guard out by opening a door into him.
Use the Crosslink to create an infinite loop that burns itself out.
Wire an elevator button to trigger something when the elevator arrives.
This is an achievement in name only. No-one admires you for punching a guy that many times.