Continuity mistake: When Tuffy's son is killed, you see his shoe fly by the camera, with his severed foot still inside. Shortly after, when you see the shoe again, it is empty, and simply covered in blood.
Other mistake: After the Joker has become a vampire, you can still see his reflection in metal poles and such while he is chasing Batman in the bloodbank. (00:47:00 - 00:49:00)
Factual error: Loosely based on the novel by Jules Verne, the entire story takes place on a remote Pacific island in the early 1860s. However, as pirates come under attack by a sea monster (in the second half of this two-part film), a modern fishing trawler or tugboat appears momentarily on the far right of the screen. (00:59:05)