Very excellant game. Sticks to a tried and true formula that works very well. Some people will not like the lack of massive innovations but the developers were obviously cautious not to try something vastly new in case it flopped.
Gameplay es very similar to previous games, but the story is a massive leap ahead, as is the game world. Very very good. The additional costumes are a nice touch too.
Only other thing to note is Mark Hamil does not voice the Joker (but his replacement is very good in his own right) and Batman's voice actor has been replaced by the voice actor of Chris Redfield (Resident Evil) he does a good job and after a while you don't even notice.