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