Revealing mistake: When Gabby and Fin are hanging off the building in Las Vegas, you can see that Gabby isn't holding on to anything in some close-up shots. (00:11:47)
Continuity mistake: Mikey dropped the wristwatch Andrew gave him and it landed face down with the bands upward. When Mikey jumped off the rock to retrieve it, the watch's face was on its side (visible to the screen) and the bands were parallel to the ground. (00:05:04)
Continuity mistake: The cursed necklace is shown emitting its evil fumes on the white paper of the letter, but the letter itself is perfectly 90° with the envelope, or at a different angle. (00:06:20)
Revealing mistake: Right after the little girl sprays the monster with bug spray, you can see the costume of the monster, it's wearing a black cap. (01:19:00)
Audio problem: The chef finally gets the bright idea to fire his hunting rifle at Morgan's fleeing vehicle. In a previous scene he was grabbing ammunition for his rifle, and he also loaded it. The rounds appeared to be high power rifle ammo, probably in the 7mm Remington magnum or .30-06 range, very common hunting rounds. When he fires his rifle it sounds quieter than a suppressed shot, however he has no suppressor on the muzzle end of his weapon. (01:09:20)
Continuity mistake: While Eddie performs "Hot Patootie", he's seated on the motorcycle with Columbia for a bit, and when Eddie stands up he's holding the mic in his left hand, but as he walks up the steps it's in his right hand, then next shot when he's facing Frank-N-Furter the mic is in Eddie's left hand, and next shot it's back to his right hand again.