Are you still playing Batman: Arkham City? Or was it set aside weeks ago, to make room for multiplayer shooters, dragonslaying and online adventures in a galaxy far, far away? You might want to pick it up again today to finish off those last few, niggling sidequests, as Rocksteady Studios has a holiday treat for you.
The Batman Inc. batsuit skin DLC is now available to download (or coming later today) to PlayStaton Network, Xbox Live Marketplace and Games for Windows Marketplace (here it is on XBLM). The game won't actually let you use the skin, or any other unlocked skins, until you beat the game... or enter this handy new cheat code, provided by Rocksteady.
Simply head to the game's main menu and, after selecting your save slot, enter in the following combination:
Left, Left, Down, Down, Left, Left, Right, Up, Up, Down
You'll apparently hear some sort of noise informing you that the code entry was successful. Once that's done, you'll be able to equip any of the batsuits you've unlocked, including the new Batman Inc look (from Grant Morrison's recent run).
Source: Rocksteady Studios