Revealing mistake: Mrs. Doubtfire sets herself on fire. When she jumps back and starts fighting the flames, it is obviously a stunt double as her face is longer.
Suggested correction: If you look carefully, the face looks pretty much the same, as well as the voice.
The reason the voice was the same is that it was probably an audio dub, which is a voice recording over someone else's voice.
Revealing mistake: After Nuclear Man destroys the cab's hood, the shot changes and there's a thick string running behind him all along the car, and the cab driver is stretching out to pull it. Probably he was activating some sort of bad FX.
Revealing mistake: Aboard the Hogwarts Express, when Harry stands beside the open window and sends Hedwig off with the letter for Sirius, surely his hair and clothes would be wildly moving about, because of the strong wind from the fast moving train.
Revealing mistake: Underdog's first costume is supposed to be a felted down (the more accurate term would be fulled) wool sweater. When wool is felted the stitches lose clear definition and usually achieve a "felted" look. It is clear that the sweater in the movie has just been switched for another smaller sweater as the stitches are still sharply defined after it has been pulled from the dryer. This is especially clear around the U. No attempt to make the smaller sweater look "felted" was made. This refers to the original costume with the solid white U, not the second costume with the yellow outlined U.
Revealing mistake: When Stan falls into the dug-out at the baseball game you can clearly see the crash mat that he lands on.
Revealing mistake: When Macaulay Caulkin has all his friends over and they are riding the rollercoaster there is a section of it missing.
Suggested correction: The "missing" track is the car loading track for the station.
Revealing mistake: When Charlie and Grandpa Joe drink the fizzy lifting drink and are floating in the air you can see the hook that is connected to the wire that Charlie is being held up by.
Revealing mistake: When the weasels are at Eddie's apartment and Roger is handcuffed to Eddie, Roger runs under the bed and drags Eddie on the floor. As he pulls him you can clearly see a board with wheels under Eddie that is pulling him under the bed. (00:38:50)
Revealing mistake: When the boys' rival team challenges them, all the boys throw their gloves down, except Yeah-Yeah. When they all go to pick them back up, Yeah-Yeah has to pretend to pick it up.
Revealing mistake: When Cody is on the jet ski inside the evil guy's hideout, he smashes through some glass. The glass smashes before the jet ski even touches it.
Revealing mistake: At the zoo, Harry looks to his right, at the 'bred in captivity' sign of the Python. In this close-up, the green plant that is below, to the side of the exhibit sign, is protruding out past where the glass supposedly is, yet this is BEFORE the glass disappears. As a matter of fact, this plant, nearest the exhibit sign, changes its position considerably throughout these shots. (00:06:50)
Revealing mistake: When Troy crouches down on the rocks, and leans down to see his reflection in the water, oddly the reflection is not reversed, yet his hair is combed the opposite way. (Did the director actually think that if Troy's hair was combed the opposite way it would pass as a reversed reflection?) Additionally, when he crouches down, the bottom button on Troy's shirt is unbuttoned, but in the reflection (as well as in the previous and following shots) the bottom button is buttoned up.
Revealing mistake: There is an obvious stunt double for Grandpa during the fight scenes.
Revealing mistake: When Tim Curry runs out of Kevin's hotel room after being scared by the inflatable clown doll he hits his knee on a table. When he hits the table and then hops away you can clearly see that he is wearing a knee-pad.
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 Madame gets off the carriage, Frou-Frou winnies to get her attention. Madame then proceeds to feed her. Frou-Frou eats from her hand. However, if you look closely at Madame's hand, it is empty. (00:03:05)
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)
Revealing mistake: When Homer placed the rocket on his fence and lit it his friend asked "Should we get behind somethin'?" That's when the rocket explodes. When you see them fly back you don't need to slow motion it because you can clearly see the wires attached to their backs.
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: When the mayor has his head shaved by the Grinch, Clint Howard grabs the clippers and shaves his own head down the middle. His hair is yanked off his head before he even moves his hand. Even better in slow motion.