The Joker and The Asylum Steal the Show
Batman is an Incredible Experience and is clearly this years Bioshock (a game with such high quality it surprises even the fans). I don't want to get into a detailed description like most reviews concerning the Free Flowing Combat & Detective elements being satisfying, or how the Stealth is slick, or how the gadgets are cool. Just know it all works well and is fun.
What I really want to let readers know is how Arkham Asylum and The Joker are really this games "Aces up it Sleeve" (see what I did there). First, the realization of the Asylum is so well done. Rocksteady has created one of best locations for a game that I can ever think of. The attention to detail, the lighting, the effects, you just feel like your in this place. Its moody and you will throughly enjoy exploring in this game space.
Lastly, The Joker. VERY SPECIAL PROPS the Mark Hamill and his voice work this time around as the joker. Mark has basiclly done for this Joker what Heath Ledger did for the joker in the film version of the Dark Knight. It's almost like Hamill took inspiration in Ledger's performance and raised the bar for voice acting, it's simply out fn standing.
My final thought you should know is that each year a game comes out of nowhere with such quality it blows the majority away in its gameplay, story, grahics, environments, etc. that gamers talk about it for years. Bioshock did it in 2007, Dead Space did it in 2008, and now Batman AA does it in 2009