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.
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.
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.
Revealing mistake: The Batcave was a stage set with no real exit for the car. So when the car exits for the first time here, one shot is looking into the cave from the tunnel as the Batmobile approaches and passes to our right. Just before the shot ends, the rear end of the car jumps upward and tire skid marks appear on the floor as the driver slams on the brakes to avoid hitting the studio wall that is out of the shot, while the audio suggests the car is still accelerating.