Here's the latest video from Batman:Arkham Asylum which shows off the various foes Batman will be facing off against in Batman: Arkham Asylum
. All the old favorites are there including Killer Croc, Joker, Batman, Poison Ivy, and Harley Quinn along with assorted filler guys that you'll be taking out between boss fights.
The only villain that seems missing is the Scarecrow who Eidos might be holding off on but he might not make the cut.
I did see the game at E3 and they've really done a good job of creating a true Batman game. The game forces you to take out clumps of bad guys one at a time and if you try to take them out en masse you won't survive for long. Instead you have to use the shadows to take out enemies one at a time and think about what you're going to do ahead of time. I do wonder how the game is going to keep things interesting for six plus hours but I guess we'll find out next month when the game hits shelves.