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