After its initial release, Arkham Asylum received downloadable content (DLC) that added new maps to the game's🌜 challenge mode, as well as the Joker as a playable character (albeit only on the PlayStation 3 and Return to🌜 Arkham versions).
Answers. To play🌜 as the Joker you have to download that add-on from the section of add-ons on the Playstation Network for free,🌜 and then go to challenge map and select the Joker to play like him. Thats all you have to do.