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