There is only one way in

Save the damsel, but is she in distress?

Complete a combo of 20 moves (any play mode)

Solve 40% of Riddler challenges

Conquer the effects of the Scarecrow's fear gas

Solve 25% of Riddler challenges

Save Dr. Young from being killed by Victor Zsasz

String up one henchman and drop him to surprise a second (any play mode)

Gain access to Arkham Mansion after it is locked down by the Joker

Defeat Bane

Save all the doctors in Medical

Escape from Intensive Treatment to the island surface