Full list of all 47 Batman: Arkham Asylum GOTY achievements worth 1,000 gamerscore. It takes around 20-25 hours to unlock all of the achievements on Xbox 360.
Take down Zsasz in the Patient Pacification Chamber
Rescue the guards and henchman from the Joker toxin in Decontamination
Survive the onslaught from the deformed Joker henchman
Escape from Intensive Treatment to the island surface
Save all the doctors in Medical
Survive the nightmare of the Scarecrow's fear gas
Defeat Bane
Gain access to Arkham Mansion after it is locked down by the Joker
Face your biggest fears and keep your sanity
Save Dr. Young from being killed by Victor Zsasz
Capture and lock up Harley Quinn
Defeat two Titan Henchmen at once
Conquer the effects of the Scarecrow's fear gas
Venture into Killer Croc's lair and come out alive
Defeat the giant Titan Ivy plant
Complete story mode on Easy difficulty
Complete story mode on Normal difficulty
Complete story mode on Hard difficulty
Time to break up this party
Complete a combo of 20 moves (any play mode)
Complete a combo of 40 moves (any play mode)
Glide continuously for over 100m
String up one henchman and drop him to surprise a second (any play mode)
Take on a beast in hand to hand combat
Catch a Batarang (any play mode)
Complete a combo of 5 moves (any play mode)
Complete a combo of 10 moves (any play mode)
Perform a perfect combo including all of Batman's combat moves (any play mode)
Ride a beast and unleash its power
Achieve 8 medals on combat challenges
Achieve 16 medals on combat challenges
Achieve 24 medals on combat challenges
Achieve 8 medals on predator challenges
Achieve 16 medals on predator challenges
Achieve 24 medals on predator challenges
Complete one predator challenge by using only Silent Takedowns and without being detected
Complete one combat challenge without taking damage
Solve every riddle on the island
Solve 5% of Riddler challenges
Solve 10% of Riddler challenges
Solve 25% of Riddler challenges
Solve 40% of Riddler challenges
Solve 55% of Riddler challenges
Solve 70% of Riddler challenges
Solve 85% of Riddler challenges
Solve Arkham's biggest mystery
100% Complete