In the Arkham Asylum stage, there are many references to the Batman Arkham series. The first is Hugo Strange in the background observing the fighters. He looks exactly like he does in Batman: Arkham City. The second is in the first stage transition (from the Main Hall to the Mess Hall) where the player is attacked by Scarecrow. He too looks like he does in Batman: Arkham Asylum. Finally, during the second stage transition (from the Mess Hall back to the Main Hall) where the player is beat up by Killer Crock, The Penguin, The Riddler & Two Face who also share their appearences from the Batman Arkham series.