Here is the full list of all 42 Gunpoint achievements. It takes around 6-8 hours to unlock all of the achievements on Windows.
Knock Fritz Gessler out of his office window.
Conceal your presence at the DataSec break-in from Mayfield.
Mock the chief of police at a critical moment.
Chicken out of telling Katie the truth at the last minute.
Create a custom mission with at least one objective.
Defeat Gessler by rewiring his gun.
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).
Slam Fritz Gessler's office door into him.
Complete a mission faster than I can.
Complete a mission that has guards with no violence, witnesses or loud noises.
This is an achievement in name only. No-one admires you for punching a guy that many times.
Beat Fritz Gessler to death.
Kick Fritz Gessler's office door into him.
Use the Gatecrashers to kick a door through a window.
Upgrade your battery capacity to the non-figurative max.
Free an innocent man at the expense of catching a guilty one.
Complete the police chief's missions without incriminating yourself.
Tell Gessler that Rooke's hired you to betray him.
Voluntarily tell Katie the truth.
Use the Dropshot to land silently from a great height.
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 with a punch.
Intimidate Fritz Gessler into surrendering.
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 into a guard.
Use the Gatecrashers to kick a door off its hinges.
Use no violence at all on a mission that has guards.
Steal Gessler's technology for Rooke.
Knock a guard out by opening a door into him.
Upgrade your Bullfrog Hypertrousers to pounce instantly.
Upgrade your Bullfrog Hypertrousers to maximum jump strength.
Use the Hushcracker to jump through a window silently (outside of the test lab).
Get knocked down by an opening door.
Leave no living witnesses to your presence on a mission that has guards.
Jump into an Enforcer to knock him through a window.
Wire an elevator button to trigger something when the elevator arrives.
Use the Crosslink to create an infinite loop that burns itself out.