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