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.
Tell Gessler that Rooke's hired you to betray 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.
Defeat Gessler by rewiring his gun.
Knock Fritz Gessler out of his office window.
Shoot Fritz Gessler.
Beat Fritz Gessler to death.
Intimidate Fritz Gessler into surrendering.
Notice the story doesn't necessarily gel with the mechanics. Become qualified games journalist.
Kick Fritz Gessler's office door into him.
Create a custom mission with at least one objective.
Complete the police chief's missions without incriminating yourself.
Use the Longshot to make a guard unintentionally shoot another (outside of the test lab).
Complete a mission faster than I can.
Upgrade your battery capacity to the non-figurative max.
Publish your personalised epilogue.
Complete the game.
Knock Fritz Gessler out with a punch.
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.
Jump into an Enforcer to knock him through a window.
Help justify my early, not entirely wise choice of game name by holding someone at gunpoint with the Resolver.
Use the Prankspasm to knock out someone who isn't standing near a power socket (outside of the test lab).
Steal Gessler's technology for Rooke.
Mock the chief of police at a critical moment.
Conceal your presence at the DataSec break-in from Mayfield.
Upgrade your Bullfrog Hypertrousers to pounce instantly.
Use the Crosslink to create an infinite loop that burns itself out.
Upgrade your Bullfrog Hypertrousers to maximum jump strength.
Use no violence at all on a mission that has guards.
Complete a mission that has guards with no violence, witnesses or loud noises.
Get knocked down by an opening door.
Use the Hushcracker to jump through a window silently (outside of the test lab).
Knock a guard out by opening a door into him.
Use the Dropshot to land silently from a great height.
Leave no living witnesses to your presence on a mission that has guards.
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.