Revealing mistake: When Ripley first burns the egg plants inside the nest, the Queen screams and moves her head. The steel rod used to hold the Queen's head to the rest of her body is easily visible.
Revealing mistake: In the scene where Ronnie visits Brundlefly for the second time we see Brundlefly walking on the ceiling and wall, however his shirt doesn't remain consistent with gravity. This is especially obvious when he pulls his shirt up to show Ronnie his new tumor and then places it back down. The shirt appears to be being pulled up to towards the sky from Ronnie's perspective. (01:07:30)
Revealing mistake: When the counselors show up at camp with groceries, Paula and Cort walk away with bags to take inside. However if you watch the reflection in the side of the truck closely you can see them sit down and wait for the scene to end. (00:17:55)
Suggested correction: One of two things 1. They could have waited until they got all the other stuff to go. 2. One could have dropped a bunch of stuff and then the other went to help.
Revealing mistake: The "blower" on the yellow Firebird never runs. NO wonder he couldn't beat the Wraith. (00:44:10)
Revealing mistake: After the bounty hunter, who changes three times throughout the movie, changes into the Reverend, he is in front of someone else who is a stand-in for the real Reverend but is obviously not.
Revealing mistake: It is obvious a dummy was used when Steve is thrown from his easy chair into the kitchen cabinet.
Revealing mistake: When Jim hits the brakes in his stolen patrol car, the two pursuing police cars turn and flip over and over. As they roll, the 'roll cannon' is visible on the underside of one of the cars (a round steel tube in a hole in the floor) and at left, the two cannon slugs from both cars bounce down the road. This device fires the slug downward, and the force behind it lifts the car when the slug hits the road, launching the car over.
Revealing mistake: When the ice-cream van is being shot at the end of the film, for a single shot you can see the driver sitting in it.
Revealing mistake: A sign's wooden support gets shot at the beginning, but you can see where the pre-prepared weak point is in the support before it gets "shot."
Revealing mistake: Later into the film Roger realises that his aunt's paintings hold some significance to the whereabouts of his missing son. He removes a cloth from the top left of a painting revealing an image of his son trapped in his bathroom cabinet. Note the cabinet door is the wrong way round to the one in his bathroom.
Revealing mistake: At the end of the film, when the main female character is done taking a shower, she tries to get out of the glass stall. Suddenly, the ghost turns on the shower to scalding hot temperatures. She is unable to get the door to open, so she punches through the glass and climbs out. As this is happening, if you look behind her, you can see that no water is coming out of the shower head, though you can still here the hissing of the water.
Revealing mistake: At the end of the movie, the main creature has the head of a human. However, in a number of shots you can see the actor's neck showing how they made the head "appear" to be attached to this creature.
Revealing mistake: The laser blasts the robots fire instantly exterminate or destroy most everything in their path. However, when the guys are shooting at them during the mall blast-out, the lasers suddenly don't do much damage at all.
Revealing mistake: At the end when Katrina's skeleton flips off Keith, you can plainly see a crew member's hand moving the arm.
Revealing mistake: When the bully's held up by Sam wires can be faintly seen.
Revealing mistake: In the Director's Cut ending when Audrey II eats Seymour, it spits out his glasses, and they land in front of the camera. They pulled this off by having a pair of glasses inside the plant's mouth that would be yanked out by a string, and another pair of glasses would be dropped in front of the camera. However, the first pair gets caught in the teeth and fall back inside the mouth, but the other pair lands on the ground anyway.
Revealing mistake: When Norman drives Dukes car into the pond, it's obvious no one is in it.
Revealing mistake: The scene in the locker room when the bullies are dunking Marty in the toilet. Marty's "body" is a fake prop used - on the naked body mysteriously there is no penis or testicles. In addition to this, despite being turned completely upside down, Marty does not struggle in the slightest as he would in real life - he does not struggle at all exactly because it is a prop body being used.
Revealing mistake: During the earlier graveyard scenes when the zombies or monsters are walking out from their graves, half the makeup is genuine prosthetics, while others are fake thrown together rubber that separates from the actor's faces.