One of the most original or wacky (depending on your point of view) costume unlocks for Batman Arkham City is the “Batman Sinestro Corp costume”
The costume can be obtained by buying the Blu-Ray 2D or 3D version of the Green lantern, this obviously means the costume can only be obtained via the PS3.
As of yet there is no in game image of the costume but below is what you can expect to be roaming the streets of Arkham city in.
Batman Arkham City is out this October. You can pre-order the collector’s edition from ShopTo on both the PS3 and Xbox 360.