Continuity mistake: When Batman and Batgirl are about to have sex on the roof, Batman lets his left hand slip down from her back to her butt. In the next shot, it's on her back again.
Deliberate mistake: When Batman enters the replica of The Joker's apartment there's no place for The Joker to hide. Yet seconds after Batman enters, The Joker comes out of nowhere to hit him with a pot.
