(at around 36 mins) As Angelique says to Pinhead "Things seem to have changed" she is standing in front of him. Then as Pinhead responds "Hell is more ordered..." she is now standing closer and to his side. This is because the original filmed line was "Things seem to have changed, I was expecting my clowns" in reference to Demon Clowns that were cut from the past segment of the film. Cutting "I was expecting my clowns" means her position 'jumps' closer to Pinhead and creates this continuity error.
Dr Paul Merchant's hair changes lengths throughout the film.He goes from bald to stubble and then back to bald.
When the Lament Configuration shoots chains out at Sharpe, and the gateway opens, look at the box in the wide shot and you will see that there are no chains coming from it.
(at around 59 mins) As Bobbi sends the Chatter Beast back to Hell, she holds up the puzzle box and shouts "Does this pathway work both ways!?". As she says this, the shot zooms in and then back out and as it does the puzzle box changes position in her hand. In the wide shot, she is holding it with the large gold dial pointed at the Chatter Beast, but in the close up shot, it is a small brown circle pointed at the Chatter Beast .
(at around 1h 1 min) After Pinhead sends the chain through Dr Merchant's throat, blades open at the business end of the chain. Dr Merchant is holding the chain tightly with both hands when it is recalled; his head is severed but his hands are shown clearly and have suffered no damage.
(at around 9 mins) When Le Merchant is offended by his wife's comments and puts the Lament Box into the travel chest, a section of the gold veneer on it has bent upwards.
The actor Mickey Cottrell is credited at the beginning of the movie as "Mickey Cotrell". At the end of the movie, in the credits list, the error is corrected.
(at around 42 mins) "Air conditioning" is misspelled as "air conditionioning" on the floor plans reviewed by the twin security guards around halfway through the movie.