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