Batman: Arkham City Lockdown on iOS has story events that aren’t available on the console and PC versions. One of these was an episode involving the mercenary, Deadshot. Another episode, added to the game today, features Poison Ivy taking over Robin’s mind:
Additionally, NetherRealm Studios, the developers of Mortal Kombat, have also optimized the game for the iPad with a higher resolution (2048 x 1536) and more visual effects and details. A Batman: Year One skin is available for download in the game as well.