If you're finished with Batman: Arkham City and sad that you've got no more bat-themed gaming to do, fret not. Batman: Arkham City Lockdown appeared on iTunes last night without herald, and is yours to download for $5.99.
Arkham City Lockdown is a one-on-one fighter with a few shades of Infinity Blade about it. It's apparently decent, so if you've an iThing, you might want to look into it. It's actually been developed by NetherRealm, so that's interesting!
Anyway, get it if you want. Or don't. It's your choice.