Batman: Arkham Asylum Getting Free DLC?

Whilst Batman: Arkham Asylum has still to hit retail shelves, the press has had copies for almost a month now, and the lucky few that have played the game over the last couple of days will have noticed that the in-game message box is now saying “New free downloadable content coming soon!”.  Naturally we’ve no idea what the in-game downloadable stuff actually is because it’s not yet available, and whilst it’s not the Joker Challenge Maps (the message is on both PS3 and Xbox 360 versions and the Joker DLC is already on the US PlayStation Store) there’s every chance that it’s still something Challenge Map based.

Thanks, radiobridge, via JustPushStart (image credit).