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