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.
Use the Longshot to make a guard unintentionally shoot another (outside of the test lab).
Complete a mission faster than I can.
Notice the story doesn't necessarily gel with the mechanics. Become qualified games journalist.
Slam Fritz Gessler's office door into him.
Beat Fritz Gessler to death.
Defeat Gessler by rewiring his gun.
Free an innocent man at the expense of catching a guilty one.
Mock the chief of police at a critical moment.
Jump into an Enforcer to knock him through a window.
Chicken out of telling Katie the truth at the last minute.
Tell Gessler that Rooke's hired you to betray him.
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).
Upgrade your battery capacity to the non-figurative max.
Knock Fritz Gessler out of his office window.
Kick Fritz Gessler's office door into him.
Catch a guilty man at the expense of freeing an innocent one.
Intimidate Fritz Gessler into surrendering.
Knock Fritz Gessler out with a punch.
Publish your personalised epilogue.
Complete the game.
Shoot Fritz Gessler.
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 through a window.
Use the Dropshot to land silently from a great height.
Use the Gatecrashers to kick a door into a guard.
Use the Gatecrashers to kick a door off its hinges.
Upgrade your Bullfrog Hypertrousers to pounce instantly.
Complete the police chief's missions without incriminating yourself.
Knock a guard out by opening a door into him.
Conceal your presence at the DataSec break-in from Mayfield.
Steal Gessler's technology for Rooke.
Get knocked down by an opening door.
Upgrade your Bullfrog Hypertrousers to maximum jump strength.
This is an achievement in name only. No-one admires you for punching a guy that many times.
Use the Hushcracker to jump through a window silently (outside of the test lab).
Wire an elevator button to trigger something when the elevator arrives.
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.
Use the Crosslink to create an infinite loop that burns itself out.