Continuity mistake: When the Batmobile is going to park (before the bomb scene) there is a sign saying "Mobey Dick Parking Only". When he is later carrying the bomb and passes by the Batmobile the sign is not there.
Continuity mistake: When Bruce Wayne escapes from the United Underworld (Joker, Penguin, Riddler and Catwoman), he climbs to the top of their hideout (Ye Olde Benbow Taverne) and jumps from the top of the roof (to the water below). But in the next shot, Bruce now jumps from the edge of the roof and dives into the water. (00:54:20)
Other mistake: When the Joker fires a missile near the end of the movie it curves to the left. The writing on the missile is backwards, showing that it is reversed footage from earlier in the film, when it curved to the right.
Other mistake: The scene where the Penguin is dehydrating his henchmen. Watch as the last henchmen is dehydrated - the shot changes to the Penguin and the Riddler. You hear the Riddler's laugh but his lips don't move until the end of the laugh.
Continuity mistake: In the helicopter scene in the first 10 minutes of the movie, Batman moves down on the ladder and stops. In that first shot you can see that there are about 10-12 rungs below him. In the next shot there are only two. Shortly after he gets attacked by the shark there are now at least four rungs below him, and yet he has not made any attempt to move up or down.
Other mistake: When Penguin and the others attack Bruce on his date in his hotel room, Penguin is the first one to charge him. Bruce takes a swing at Penguin's face and he goes flying from the blow. You don't even need to slow the film down to see that Bruce totally misses him.
Continuity mistake: The amounts of colored powder in the vials change in every shot; sometimes they are all equal, other times there are large differences between them.
Other mistake: When the Batboat is approaching the submarine before the final fight, the shot from the periscope is an overhead shot, not a surface shot like all the others in the film.
Revealing mistake: Whenever the moving Batmobile is emitting flames from the afterburner, like when it leaves the Batcave for the first time, an object is hung below the exhaust port that resembles a camcorder. The gadget is part of the equipment added to make the car shoot flames while moving. During the TV series, flames are only seen in close-up of the car motionless, as this was a prop comprised of a copy of just the last few feet of the car. On TV, the car's rear license plate is visible. In this film, it's partially blocked by the added equipment. (00:03:35)