Here is the full list of all 44 Nuclear Throne achievements. It takes around 200 hours to unlock all of the achievements on Windows.
We hereby sincerely apologize.
Defeat Captain.
Get 100% of the unlocks.
Defeat Captain as Rogue.
Reach Level Ultra as Skeleton.
Sit on the Nuclear Throne as headless Chicken.
Defeat the Technomancer as Steroids.
Defeat Mom as Rebel.
Reach the Nuclear Throne in under 10 minutes as Plant.
Unlock a Golden Disc Gun or Golden Nuke Launcher.
Reach 2-1 on Hard Mode as Chicken.
Reach the Nuclear Throne with Melting without choosing Rhino Skin or Strong Spirit.
Reach 4-? as Crystal.
Unlock all Crowns as one character.
Play as Frog.
Reach 2-? as Eyes.
Unlock Hard Mode.
Unlock a Golden Weapon for every character.
Defeat Hyper Crystal as Horror.
Defeat the Technomancer.
Defeat Hyper Crystal.
Loop as every character.
Defeat Mom.
Reach 7-3 on a Daily.
Unlock a Crown as any character.
Reach Level Ultra as any character.
Loop past the Nuclear Throne.
Defeat Throne II.
Loop the game.
Reach 5-?.
Unlock a Golden Weapon as any character.
Reach 3-?.
Defeat Horror.
Reach the Nuclear Throne.
Defeat the Nuclear Throne.
Eat a Hyper Weapon as Robot.
Reach 6-1.
Defeat Lil Hunter.
Reach 5-1.
Die.
Defeat Big Dog.
Reach 3-1.
Reach 2-1.
Defeat Big Bandit.