Revealing mistake: Riggs handcuffs himself to the depressed businessman. They jump off the building but they're not handcuffed to each other anymore. They used plastic cuffs which could separate during the stunt in case anything went wrong. They break just as they jump, so they grab each other's hands to stay in contact. After they land the cuffs are attached again. (00:31:00)
Revealing mistake: Mac and Dillon go after the Predator. The Predator is sitting in a tree, and Mac points him out to Dillon. They both agree that they see it and take position. Mac crawls underneath the alien and is killed by his laser. The Predator then sees Dillon and lasers his arm off. Dillon's arm falls to the ground with the gun firing. Quickly Dillon turns and reaches for the machine gun around his neck. When he turns you clearly see his bloody right stump and his right arm sticking out the bottom of his jacket. [Note: As far as I can work out, this has been cunningly edited out of the UK DVD version].
Revealing mistake: Toward the end, when they have killed the shark and are all floating about in the water, you can see that the horizon is a painting. The water is even lapping up against it. (01:20:30)
Revealing mistake: When Jack is hanging out of the truck you can see him standing on the hood of the car which Lydia is driving. At some points we get camera view from the back seat of the car. In some angles the mirror inside the car disappear. This is to prevent us from seeing the camera. (01:04:15)Mortug
Revealing mistake: The footage when the vampires are entering the cave. Later when they are exiting the cave, the waves are flowing backwards. The footage has been reversed. (01:17:05)
Revealing mistake: After Johnny leaves, they show Baby standing on the porch of her family's cabin. If you look in the background you see two people waiting for their cue before they start walking. (01:24:30)
Revealing mistake: When David drives through the outer wall of the bakery products store, in the side shot the wall first bends, then it breaks as the car goes through. Also, the next back shot is a repetitive action, although the window breaks quite differently in both shots. (00:50:45)Super Grover
Revealing mistake: When the Marines are jogging through the training camp complex, singing "I don't know but I've been told..." you can see the British road junction markings on the tarmac underneath them. There is little evidence to suggest that there was any attempt to disguise or remove them.
Revealing mistake: When we see Dark Helmets' hoverjeep in the desert, watch the front end: you can clearly make out the edge of the mirrored box they used for the "hover" effect.
Revealing mistake: Near the end of the film, when Neal is on the final L train home, we see the train pull away from the station. When Neal returns to the station to find Del, the footage of the train leaving is played backwards - you can briefly see a man walking backwards at the top left of the screen.
Revealing mistake: When being chased down the street and Jackie is in the horse carriage, he throws a guy through a window. You can see the glass has been pre shattered and therefore easier to break.
Revealing mistake: When the eye is flying toward Bobby Jo, you can see the rig holding the eye as it flies and the wire when it enters her mouth. (00:41:45)