When Amelia puts the dinner in the oven it is on the top rack, about 4" from the top of the oven. Later, when she throws the Zuni fetish doll into the oven, the dinner is still smoldering in there, but now it is on the bottom of the oven and there are no racks (allowing room for the doll to dance around and scream).
The two times that Amelia telephones her mother, the numbers she dials are different.
When Amelia is first attacked by the Zuni fetish doll, it is in her living room and she goes nowhere near her apartment's front door. After managing to trap the doll in the suitcase, she then immediately runs to the kitchen and gets a screwdriver, then runs to her front door, where apparently the bolt has been bent, trapping her in. But why did she go and get the screwdriver before she even knew the bolt was bent?
In the film's first segment, during the first classroom scene, Julie's pose is changed from two continuous shots (when she starts talking and when she asks the question).
When Millicent hugs the little girl, she brings her so close she can touch her head with her chin, but in the next shot they are not so close.
When Amelia calls her mother at the beginning of the film's third segment, she dials seven numbers on the rotary phone, but when she calls her again at the end of it, she dials eight numbers.
Darkroom chemicals are not flammable.
In the film's second segment, Millicent removes a book from the shelf labeled "Voodo and Satanism." Not only is the word "Voodoo" misspelled on it, but the book's title has obviously been written on it by hand.
When Amelia crouches down with the knife at the end of the film's third segment, the stage light keeping her face lit for the camera loses track of her for a moment.
A mistake is visible during the opening scenes of the film's third segment while Amelia is talking on the phone with her mother. At least twice it can be seen that one of the panels making up the ceiling of the set is askew, showing empty space behind the surface of the ceiling.
When Amelia calls her mother at the end of the film's third segment, her face and mouth can be seen briefly and her teeth are clearly normal-looking, unlike just a few minutes later when she shows that her teeth now resemble the Zuni fetish doll's.
When the Zuni fetish doll bites into Amelia's neck, her screams do not match her mouth movement.
When Amelia has the Zuni fetish doll in the oven and is holding the door closed, you can clearly see the tubing that pumped the blood from when the doll bit her neck.
The wire that is used to make the Zuni fetish doll's chain fall off is visible just over its head before the chain falls.
When the Zuni fetish doll is cutting itself out of the suitcase, a crew member's hand can be seen at the bottom left of the frame, holding the suitcase in position.