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.
Create a custom mission with at least one objective.
Use the Prankspasm to knock out someone who isn't standing near a power socket (outside of the test lab).
Notice the story doesn't necessarily gel with the mechanics. Become qualified games journalist.
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.
Slam Fritz Gessler's office door into him.
Knock Fritz Gessler out of his office window.
Intimidate Fritz Gessler into surrendering.
Defeat Gessler by rewiring his gun.
Shoot Fritz Gessler.
Kick Fritz Gessler's office door into him.
Publish your personalised epilogue.
Complete the game.
Beat Fritz Gessler to death.
Knock Fritz Gessler out with a punch.
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 battery capacity to the non-figurative max.
Upgrade your Bullfrog Hypertrousers to pounce instantly.
This is an achievement in name only. No-one admires you for punching a guy that many times.
Steal Gessler's technology for Rooke.
Chicken out of telling Katie the truth at the last minute.
Voluntarily tell Katie the truth.
Mock the chief of police at a critical moment.
Use the Crosslink to create an infinite loop that burns itself out.
Complete the police chief's missions without incriminating yourself.
Conceal your presence at the DataSec break-in from Mayfield.
Upgrade your Bullfrog Hypertrousers to maximum jump strength.
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.
Use no violence at all on a mission that has guards.
Get knocked down by an opening door.
Jump into an Enforcer to knock him through a window.
Use the Dropshot to land silently from a great height.
Wire an elevator button to trigger something when the elevator arrives.
Knock a guard out by opening a door into him.
Leave no living witnesses to your presence on a mission that has guards.