When Fleming finds the floor plans and the Bat attacks him, the paper of the plans appears to be black, but when the Bat is carrying it after the murder, it's white.
Near the end, the Bat shoots the police officer and he falls on the floor. Moments later, the Bat is shot and falls to the floor also, but the body of the policeman is no longer on the floor.
When Cornelia is trapped in the hidden room, she runs out of oxygen far too quickly. The room is large enough to have plenty of air, especially with the others searching the house for her.
Warner explains that he fixed a leak by "packing the elbow." To fix a leak, you pack a faucet or a valve, not an elbow.
The Bat uses a suction cup and a glass cutter to cut a hole in the glass in order to reach in and unlatch the door. The circular piece of glass attached to the suction cup is twice as thick as the glass from which the hole has been cut. The glass attached to the suction cup is also too thick to cut a hole in using a simple glass cutter.
Obvious stunt double for Price when the fight with Bat ensues in doctor's lab.