Continuity mistake: In the scene where Pinhead is in the church, he stands behind the table, and the candle to the right of him is straight. He then pushes the cross off the front, look at the candle, it is now on a slant then in a split second the candle is straight again as if it had never been touched.
Continuity mistake: At the end of the film Pinhead tricks Joey into giving him the puzzle box by posing as her dead father. As soon as she hands the box over he takes a knife (or sickle or whatever it is) from his belt with his left hand and poises to strike. Then it cuts to a shot from behind and he's now gripping the knife with his right hand.
Trivia: When Joey's television set is flipping through the channels all by itself, on one of the channels is an interview with Tony Hickox, the director of the film.
Joey: Oh, Doc. No.
Camerahead Cenobite: Have you seen what he did to me, you little bitch? Have you seen?
Pinhead: Unbearable, isn't it? The suffering of strangers, the agony of friends. There is a secret song at the center of the world, Joey, and its sound is like razors through flesh.
Joey: I don't believe you.
Pinhead: Oh come, you can hear its faint echo right now. I'm here to turn up the volume. To press the stinking face of humanity into the dark blood of its own secret heart.