BigOLB

Continuity mistake: When Joker and his goons are trashing the paintings, Joker writes "Joker Was Here" on the painting by the statue. In the next shot the painting disappears.

BigOLB

Revealing mistake: Right after Joker falls off the top of the cathedral, Batman and Vicky fall too and we catch them three times before Batman's grapple digs into the stone. On the second and third time you can actually notice Vicky's face expression doesn't look one bit scared, so you know they're not falling. You can also see there's a screen in the background. (01:58:40)

BigOLB