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