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