Continuity mistake: In the shot of the alien's tail wrapping around the back of Lambert's legs right before it kills her, the floor is different to what it was before, there is water suddenly falling from the ceiling when there wasn't before and her trousers have changed from white to blue. This is because that shot was originally intended to be used when Brett was killed.THGhost
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.
Factual error: When Brian fires a rifle at the shark from the boat, he fires the rifle multiple times very quickly. The rifle he is using is a bolt action rifle, which must have a bolt part moved before each fire. He does not touch the bolt.
Visible crew/equipment: Young vampire Danny floats away from the window after being confronted with a crucifix. The effect is quickly ruined when the boom he is sitting on can be seen moving him for 8 seconds. (01:43:40)
Continuity mistake: When Watson is conned by the prostitute who says she knows Mary Kelly, she lures him into a closed alley. After Watson has called the police and subdued the attacker, 2 constables arrive and arrest Watson, but as they all leave, a third constable comes from behind the camera. Either he magically appeared, or he walked through the wall behind.