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