Revealing mistake: Mirrors were used to make the corridors appear longer, early in the film when Brett is complaining to Parker about the way they are treated by the company you can see their reflections in the mirror behind them as they walk down the corridor. It's only for a second as they are moving off camera but you can see them in their white overalls.
Revealing mistake: There is a scene which features a nighttime view of Carfax Abbey, Dracula's home. This movie was set in the late 1800's/early 1900's, but if you look closely at the left-hand portion of the screen, you will see the lights of an airplane as it flies in the skies above the castle.
Revealing mistake: You can see the stick making the finger move when it's in the box. (00:38:20)
Revealing mistake: As Holmes and Watson are riding home from Watson's stay in prison, in the background double traffic lines are visible as are concrete traffic barriers. These are a modern invention and out of place.
Revealing mistake: You can see Jackie's knuckles are already bloody BEFORE she starts pounding on the closet door.
Revealing mistake: When Dr. Menard is driving and discussing the zombie plague with the visitors, the "clean" part of the jeep's windshield (i.e. the path of the windshield wipers) appears to be cut out of the glass (probably to provide a better view of the actors and prevent the camera being reflected on the glass).
Revealing mistake: At the end of the movie, when Ben stakes vampire Susan in the heart, she throws her head back in pain and you can see her real teeth behind the fake vampire teeth.