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