(at around 21 mins) In the werewolf scene, when the hunters arrive to kill the werewolf, the young one hands the older one a box containing 3 silver bullets. The older hunter drops the bullets and as he is bending down, we see all 3 on the ground. A few minutes later the older hunter loads a silver bullet and shoots the werewolf. We then see Tony beginning to change. The older hunter kneels down to get another bullet and we see 3 intact bullets on the ground.
Near the beginning of the movie, James and Gemma chicken out of attending the Waxwork tour with their friends and are not mentioned to the staff inside. However, near the end of the film, the butler Junior calls James and tells him to arrive at the Waxwork with Gemma at midnight to meet their friends Mark and Sarah.
When China enters Dracula's dining room, from the front Dracula is sitting at the dining table. When it cuts to a back view on Dracula, however, he's standing instead. In the following side shot, Dracula is seated and then he stands up.
(at around 52 mins) When Sarah is in Mark's attic, she looks at a book of the Marquis de Sade in a trunk and it glows with white light. When Sarah looks up, hypnotized by the book when it glows, her left hand runs up to the top of her dress. However, in the very next shot, Sarah's left hand is suddenly down and it runs up to the top of her dress all over again.
(at around 6 mins) In an early scene, while a professor lectures about the Lithuanians falling to the Nazis, a phrase on the blackboard, very clearly seen, asks, "Facism Does It Work" It is spelled f-a-s-c-i-s-m. One wouldn't expect a college professor, who specializes in the subject, to make the common spelling error.
Most "waxworks" move or blink their eyes.
(at around 34 mins) What is supposed to be a solid wall slightly gives away when China leans against it during her fight with the vampires.
(at around 32 mins) In the vampire scene, China is in the kitchen with what's supposed to be her fiancé. The fiancé is strapped to the butcher's block with his left leg stripped of flesh and muscle from the knee down so there's nothing but bone. A rat is seen gnawing on the bone causing him pain. Trouble is, all the nerves were stripped away so he shouldn't have been feeling pain.
(at around 50 mins) While Inspector Roberts is examining China, shots alternate between those of the actual actress and an obvious fake model.
When Mr. Lincoln reaches out and grabs Johnathan's shoulder (41:33), Mr. Lincoln is clearly wearing glasses, but when the scenes cuts to Mr. Lincoln two seconds later, his glasses have disappeared.
(at around 1h 14 mins) When Mark walks with Sarah to leave the Prince's Chamber to go into the hall, the back of a set and a camera cable on the floor are seen instead through the doorway when they pass through the curtains.
(at around 54 mins) In the mummy's tomb are seen a Mexican Red-Knee Tarantula and a Boa Constrictor, both native to the Americas, not Africa.
(at around 5 mins) Near the beginning of the film, a moving shadow of a microphone stand is visible on Sarah's dress when she and China first talk to Mr. Lincoln in front of the Waxwork.