Revealing mistake: When Pinhead is killing the patrons at the club and they are running away to try and escape, you can see some of them laughing instead of screaming like they should be.
Revealing mistake: After Joey runs from the club into the street and a car swerves to avoid her, it hits a lamppost which causes sparks; but look closely and you can see that the sparks appear just a split second before the car actually hits the post. The sparks were rigged and set off a second too early.
Revealing mistake: When Joey gets "cut" by the chain in the hospital in the beginning, pay attention. In the shot where she gets "cut," you can plainly see all that happens is the chains slap a little blood on her ankle without any signs of actual damage. Then, a few shots later, there's a very quick closeup of the "cut," and you can see that all they did was paint a little gooey "blood" over the top of her pantyhose, which aren't ripped through at all. (Nor is there a visible cut, either).
Revealing mistake: When Pinhead kills Sandy, his chains attack her, then they lift her up, and her stunt double is visible because her hair is much shorter and her face is completely different.
Chosen answer: It's a piston. 2 piston rods are jammed through his head and they move powered by something unknown. You can see the crank shaft and part of some sort of cylinder. A piston is part of an internal combustion engine. It's part of his cenobite form since he liked cars.
lionhead