Character mistake: When Ripley interfaces with Mother for the first time and sees the special order, an instruction reads as "Insure return of organism" rather than "Ensure return."
Continuity mistake: In the beginning, when Mike and Jody raise the hood on the car, Jody's hand holding on to the hood alternates between his right and left hand over three shots. (00:13:10)
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.
Continuity mistake: When the stairs are first shown, there's carpet up the middle of the stairs. At the end when they flee the house it's gone.
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)
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.
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.
Factual error: On the left-hand side of Lucy's front door, you can see a blue and white shield. This is the trademark of the Dutch Heritage organisation, which protects monuments such as old city buildings. These signs did not exist in the 19th Century. (00:48:00)
Continuity mistake: The babysitter answers one of the early calls saying "Robert, I don't think this is very funny." The pencil and papers have completely changed position on the table. (00:07:30)