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