(at around 39 mins) When Bibi removes her bra, shot before they were kissing each other, but now her date is farther away so a shot of her breasts can be made.
(at around 1h) When Shirley asks Rick for second time does he want his treat, her hair is different in two following shots.
(at around 1h 30 mins) Shape of the cross formed by a hole changes throughout the shots at the end of the movie.
(at around 21 mins) In a scene involving the preparation of a Halloween party, a student can be seen briefly stacking cans of Coca-Cola onto a table. The Coca-Cola cans feature the Sundblom Santa Clause which is an annual Christmas marketing campaign by Coca-Cola just before Christmas and not as early as October (when the party takes place). This may possibly indicate this portion of the film was filmed around December or just after.
(at around 1h 15 mins) Demonic Rick tells Father Bob that he broke the 5th Commandment "Thou shall not kill," but it is actually the 6th Commandment that says "You shall not murder." The 5th Commandment is "Honor thy father and thy mother."
(at around 8 mins) When Mouse has her famous dream sequence, and cuts to the scene were her mouth is ripped off, you can clearly see were the fake mouth was simply put over her real one, to make the effect. Possiblely done over the actresses real mouth, or a dummy face made to look like the actress. Noticeable in HD.
(at around 1h) When Rick's hand is being crushed, his words don't match the actor's mouth movements.
When the demons speak, their scary voices don't match the actors' mouth movements.
(at around 1h 1 min) There is a scene where Johnny meets Bibi after he was told to go wake up Father Bob and asks her if she's alright even though he just saw her. Then he is finally seen going to wake up Father Bob.