Continuity mistake: After Hall has been shot in the leg in the simulation of LA 1937 the hole in his trousers and his injury disappear, as seen in the fight sequence at the pool. Hall even uses his leg to hit the bartender in the stomach, what would have made this very painful if he had been shot there.
Continuity mistake: When Ben Jordan and Stan are walking around the fountain, they walk past a long glass railing. The white sneakers of the cameraman can be seen in the reflection on the glass. You know it's him because he stops walking when they stop and continues walking when they do.
Character mistake: When Amy goes to Virgil's house to apologize, Virgil tells Amy that the tree is exactly 14 steps away. However he then leads her there by taking 17 steps.
Deliberate mistake: In the scene where Alicia Silverstone and Dave Foley are in the porno store, they cut to a guy standing behind a counter. All of the explicit shots of the videotape covers on the countertop are blurred out.
Revealing mistake: In the widescreen Blu-ray version, when Pinhead is brought to life, you can see the side of the puppeteer's hand tilting him up. The movie was originally shot for home video with the intent of being cropped down to fullscreen. The Blu-ray version presents the original uncropped widescreen version, unfortunately causing this mistake to be caught in shot.
Factual error: While Nate and his business associates are driving around in downtown Baltimore, the Key Bridge (which spans Baltimore harbor) is visible in the background. The movie was set in 1954; the Key Bridge was built in 1972, 18 years later. (01:33:55)
Continuity mistake: Jennifer manages to thwart the nefarious plan of the kids who want to cuff her in the subway. During the scene, Heidi Lenhart's left hand grips the bar in close-ups, does not in other shots. (00:27:20)