This guide is now essentially done, but I welcome suggestions on making some parts easier to understand. I don't explain self-evident achievements and this guide obviously contains spoilers.

Postat inițial de Tom Francis:

Gunpoint has 44 achievements on Steam – that’s only 5 less than Deus Ex 3. Only one is inevitable in a given playthrough, and that’s for completing it. The rest are a mix of acknowledging very distinct playstyles, encouraging you to try new gadgets, recognising insane, obsessive or impressive decisions, letting you know certain feats are possible, and in one case helping you understand what just happened (some testers don’t realise what’s happening when they make an infinite loop in Crosslink). A few are secret to surprise you, and a few are secret to avoid plot spoilers...

NOTE: Since launch, 2 achievements have been removed, there are now 42 achievements total.


Achievement Title:
"Official Achievement Text/Hint."
Instructions on how to easily obtain the achievement, may also include screenshots/videos.

All videos are in 1920x1080, if you don't set the youtube player to at least 720 they'll look terrible.

Please leave any suggestions for changes in the comments.

Gentleman:
"Use no violence at all on a mission that has guards."
Hitting a guard with a door you just kicked down doesn't count towards your violence rating.
See Perfect Gentleman

Ghost:
"Leave no living witnesses to your presence on a mission that has guards."
Either don't let anyone see you or kill anyone that sees you.
See Perfect Gentleman

Perfect Gentleman:
"Complete a mission that has guards with no violence, witnesses or loud noises."
Old Suggested Mission: "Rooke: The Prototype"
New/Better Suggested Mission: "Collins: Intex"
Thanks to Telmo Trooper for this suggestion.

I Am Better At This Than Tom Francis:
"Complete a mission faster than I can."
Suggested Mission: "Rooke: Guarded"

I’ll Aim When I’m Dead:
"Upgrade your Bullfrog Hypertrousers to pounce instantly."
These "max x stat" achievements are easy as you can reshuffle your stat points at any time. Max jump power first as it's most useful, then spread those points around to max charge speed and battery slots to get all 3 achievements.

I Taste Battery Acid:
"Upgrade your battery capacity to the non-figurative max."
These "max x stat" achievements are easy as you can reshuffle your stat points at any time. Max jump power first as it's most useful, then spread those points around to max charge speed and battery slots to get all 3 achievements.

I May Be Some Time:
"Upgrade your Bullfrog Hypertrousers to maximum jump strength."
These "max x stat" achievements are easy as you can reshuffle your stat points at any time. Max jump power first as it's most useful, then spread those points around to max charge speed and battery slots to get all 3 achievements.

Open Door Policy:
"Knock a guard out by opening a door into him."

So This Is Why People Don’t Like Me:
"Get knocked down by an opening door."

Necessary Force:
"Jump into an Enforcer to knock him through a window."

Ding:
"Wire an elevator button to trigger something when the elevator arrives."

Cat Burglar:
"Use the Dropshot to land silently from a great height."
After buying Dropshot take a high arcing jump off a tall building.

Not Really A Prank, Man:
"Use the Prankspasm to knock out someone who isn't standing near a power socket (outside of the test lab)."
Wire any input to a power socket, then that power socket to anything else. When you activate the input the output will become electrified.

Crossfire:
"Use the Longshot to make a guard unintentionally shoot another (outside of the test lab)."
Suggested Level: "Rooke: Three for All"

On The QT:
"Use the Hushcracker to jump through a window silently (outside of the test lab)."
From the purchase menu select "Try It" to learn how to use the Hushcracker. Use the Hushcracker outside of the "Try It" level.

Breaking And Entering:
"Use the Gatecrashers to kick a door off its hinges."
Buy Gatecrashers, run into a door outside the "Try It" level.

Low Flying Doors:
"Use the Gatecrashers to kick a door into a guard."

Might As Well Have An Achievement For That Too:
"Use the Gatecrashers to kick a door through a window."

Privacy Is Dead:
"Hack every laptop in the game, for no compelling reason."
ACHIEVEMENT REMOVED
Screenshot album of all laptop locations in progress.

Short Circuit:
"Use the Crosslink to create an infinite loop that burns itself out."
Wire a few things into a loop that self-perpetuates.

Mission Architect:
"Create a custom mission with at least one objective."
Go into the Level Editor and place one objective-class object.

Clean Record:
"Complete the police chief’s missions without incriminating yourself."
Don't get caught on any cameras during Mayfield: The Room, then be sure to give him the real file as it's a fake he uploaded to try and catch you lying.

Hammerhead Snark:
"Mock the chief of police at a critical moment."
Let Mayfield discover your involvement, then during your final conversation with the police chief (mission: "Mayfield: The Room"), choose either "I hope you have a good morgue. And I've been there, you don't." or "Shouldn't you be hoping I have a bad one?"
Looks like this one is a lot more complicated that I thought. Check this guide by Seemo

Title Finally Relevant:
"Help justify my early, not entirely wise choice of game name by holding someone at gunpoint with the Resolver."
Buy the gun, aim it at any guard outside of the "Try It" level.

Acknowledged Ludonarrative Dissonance:
"Notice the story doesn’t necessarily gel with the mechanics. Become qualified games journalist."
After beating the game, when "updating your blog" choose the 3rd option each time.

Open Ended Grudge:
"Take your final enemy out in each of 8 known ways."
ACHIEVEMENT REMOVED
Complete the achievements Knuckle Down, I Just Really Don't Like Gessler, Why Don't You Just Shoot Him?, Not Worth The Bullet, Seven Story Takedown, Sorry, Were You Using That?, Those Intex Models Jam, and Works Both Ways from the Secret Achievements list.

Case Closed:
"Complete the game."

Case Filed:
"Publish your personalized epilogue."
After beating the game, update "your blog" and click "publish" when finished.

Coming Clean:
"Voluntarily tell Katie the truth."
After the mission "Collins: The Recording" choose the dialogue option "Uh, there's something you should know about that." followed by "It was me. I didn't kill Selena, but the footage showed me there. I had to wipe it."

Almost Honest:
"Chicken out of telling Katie the truth at the last minute."
After the mission "Collins: The Recording" choose the dialogue option "Uh, there's something you should know about that." followed by "It was... ..MOV format."

Intex Sympathiser:
"Tell Gessler that Rooke's hired you to betray him."
At the end of the mission "Gessler: Acquisitions" choose the dialogue option "Yes, but there's something you should know about it." followed by "It's a fake, and there's a tracker. Rooke had me help set it up."

Rooke Sympathiser:
"Steal Gessler's technology for Rooke."
Don't choose the dialogue options listed under Intex Sympathiser. Then accept the $0 text only mission from Gessler in which he insults you.

Cover Up:
Mission: "Mayfield: The DataSec Recording"
"Conceal your presence at the DataSec break-in from Mayfield."
Lie to Mayfield about your involvement.

Let It Go:
"Free an innocent man at the expense of catching a guilty one."
Choose and complete the mission "Jackson: The Truth"

For the achievement directly above and directly below this text, you can take a shortcut and not have to play the whole game twice by copy-pasting the savegame folder (C:\Program Files (x86)\Steam\SteamApps\common\Gunpoint) to a safe location. Play the "Jackson: The Truth" mission, quit out and use the backup of your save to overwrite your save in the game directory. Load up the game again and this time play the "Rooke: The Killer" mission AND finish the game. that way you don't have to play from the start twice. Thanks to user Murphy's Lawyer for this info.

Payback:
"Catch a guilty man at the expense of freeing an innocent one."
Choose and complete the mission "Rooke: The Killer", then complete the game ensuring you defeat the killer waiting outside Gessler's office in the final level.

Knuckle Down:
"Knock Fritz Gessler out with a punch."
After either Not Worth The Bullet or Those Intex Models Jam, jump onto Gessler and punch him once.

I Just Really Don't Like Gessler:
"Beat Fritz Gessler to death."
After Knuckle Down, keep punching Gessler.

Why Don't You Just Shoot Him?:
"Shoot Fritz Gessler."
After Not Worth The Bullet or Those Intex Models Jam, shoot Gessler.

Not Worth The Bullet:
"Intimidate Fritz Gessler into surrendering."
Buy the gun, de-wire his desk switch and wire the camera to the door. Aim the gun at Gessler and walk into the camera. Press SPACE to go through the dialogue while keeping your gun trained on him, at the end of the dialogue he drops his gun. This easily chains into Why Don't You Just Shoot Him? or Knuckle Down, and is the easier of the two possible ways to set up Seven Story Takedown and Works Both Ways. Some users reporting this achievement bugged if you've gone the whole game without ever shooting anyone.

Seven Story Takedown:
"Knock Fritz Gessler out of his office window."
Very buggy, 90% of the time I attempt this Gessler slides very slowly down the side of the building which didn't count for the achievement. Wire his gun to the button, wire the camera to the door, pull out the resolver and walk into his office. Without advancing the dialogue, walk him slowly back 'til he was against the window. Put away the resolver and he tries to shoot, as he fails and tries to take out another gun, pounce him.

Sorry, Were You Using That?:
"Kick Fritz Gessler's office door into him."
Buy the door kicking ability, de-wire Gessler's desk switch from the door, and run at the door.

Those Intex Models Jam:
"Defeat Gessler by rewiring his gun."
Wire Gessler's gun to the desk switch, wire the camera to the door, jump through the camera field straight at the door and when Gessler tries to shoot you the door shuts behind you instead. Easily chains into Why Don't You Just Shoot Him? or Knuckle Down.

Works Both Ways:
"Slam Fritz Gessler's office door into him."
After either Not Worth The Bullet or Those Intex Models Jam walk or tackle Gessler to the left into the path of his office door then flip the switch.

Alright, Have one! Just Stop!:
"This is an achievement in name only. No-one admires you for punching a guy that many times."
Tackle any enemy in the game then punch them 100 times in a single go.
This achievement WAS bugged. "4JUNE2013-Fixed a bug preventing the game from rightly chastising you for excessively punching the same guard." But has since been fixed.