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