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