Revealing mistake: While driving the red truck through the rolling house, Dorothy is mounted on the back of the truck. There are some very sensitive and fragile instruments located on the top sides of Dorothy that stick up above the cab of the truck. These would certainly have been torn off while crashing through the walls of the house, turning Dorothy into a useless pile of junk.
Revealing mistake: When Sandman is in the truck of sand and the cop climbs up to catch him, you can see the edge of a platform uncovered. The platform is clearly there so the cop could walk without sinking - he stops right where the platform ends.
Revealing mistake: Watch carefully as the statue falls on the bartender. It barely touches his chest and rests on his left thigh. As the bartender slumps dead you can see a wide open gap between his whole upper body and the statue. Even if it crushed his thigh it would not have killed him so quickly. When the bartender slumps down the statue rocks freely as he brushes against it; obviously a styrofoam replica.
Revealing mistake: When Sarah is making her way to the baby Stego, just before she gets on her belly and crawls closer to it, you can see the kneepads she has on.
Revealing mistake: When the Enterprise is leaving space dock, look at the right (starboard) side of the ship. You can see the shape of the mounting arm the model was mounted on, even though it was blacked out to look like space, and it also blocked out the bottom of the dock. The footage was reused from Star Trek: The Motion Picture.
Revealing mistake: When Solina is crawling on the wall, whenever she turns her head, her long hair turns with it, instead of falling freely downward toward the floor. (01:05:20)
Revealing mistake: In the disco scene, the DJ is playing music, but the Pioneer decks and the DJ Mixer are not even turned on, as no lights are showing.
Revealing mistake: Each crew member has a monitor on their spacesuits that they use whenever they are exploring the caves. Whenever the monitor is shown, each crew member's individual heartbeat is shown in the lower left corner of the monitor. But no matter which heartbeat is shown, every time a heartbeat on the monitors is shown, it is always the exact same heartbeat, despite the various changes in panic and stress throughout the movie.
Revealing mistake: The final scene is filmed in Brant Rock MA, and the weather is blatantly CGI. If you notice almost everyone is bone dry in a supposed driving rain storm. Look especially at the character perched on top of the submarine tower. For contrast note the "pizza delivery" scene where it is raining heavily and everyone involved is soaking wet.
Revealing mistake: There is an obvious stunt double for Grandpa during the fight scenes.
Revealing mistake: There is a shot right after the first time the clerics are entering the city from the nethers that you see an APC patrolling the wall road above the entrance. In that shot two shadows are being cast on the road. As the CGI APC passes through them they simply don't cast a shadow on it as they should. (00:08:40)
Revealing mistake: After Pola Ivanova sneaks out of the baths, she climbs into the car with General Gogol, who can be seen to be a double and not Walter Gotell. (01:07:20)
Revealing mistake: At the beginning when the ruler is making his speech, you can see his modern day fillings in his upper molars.
Revealing mistake: When the train plummets into the basement, the windows never seem to smash nor crack, nor does the paint on the train ever seem to scratch the slightest bit. (01:34:15)
Revealing mistake: During the draining of the water in the dish, some shots show the water moving backwards. For instance, at a particular moment, masses of water jump up, arc toward the opening, and fall in it. The most likely reason is that, during the filming, the special effects people took a shot of a replica of the dish filling with water, then edited it the other way to show that the water was emptied from the dish. (01:42:00)
Revealing mistake: Utility poles are visible in the scene of the Japanese aircraft carrier launching planes for the first attack on Midway.
Revealing mistake: 1955 skateboard chase scene around town square. Note in this scene a metal device has been added between the kicktail and the back truck of the skateboard to create the sparks, then disappears and reappears throughout the whole chase scene. (01:03:40)
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: Why is there a full moon every night?
Revealing mistake: When three of the turtles are playing Trivial Pursuit and Leonardo runs in to announce Splinter is alive, you can see a wire coming out of Raphael's shell. I guess it's for the animatronic head, but it's visible. (00:59:30)