Other mistake: In the beginning of the movie, when you first see Mary-Kate (aka Mel) and Ashley (aka Ally), Mary-Kate walks off without ever closing her locker.
Continuity mistake: The boys go out in their boat to water ski, only to find that Jones has built a huge dock that blocks their way. No matter. The boat does not contain skis nor a tow-rope anyway....
Continuity mistake: When Sly is in the attic, and the fake power dude comes up to kidnap him, Sly uses a ski to "hit him in the gonads". But if you look closely at his face, the guy who was hit in the nuts wasn't the same guy that fell down the stairs.
Deliberate mistake: When Tarzan fights with the leopard, it scratches his chest. However after they fall into the pit and Tarzan comes out carrying the dead leopard, the scratches on his chest have amazingly healed. [It is a long-standing Disney tradition that no evidence of violence is shown on screen. Still a mistake, but there's why].
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.
Continuity mistake: When Sam and the other girl fall down the mountain, at one shot Sam unlocks the girls snowboard and it drops down the mountain but at one shot before the ski patrol throws the rope down to them you can see (for a second) on the right side of the girl, the corner of the snow board. Then she doesn't have it.
Continuity mistake: When Sikes is put into the headpiece and Claw has the power turned up full force the chin strap is first around Sikes's chin, then it isn't, then it is.
Continuity mistake: When the Iron Giant follows Hogarth home they cross a railwayline and the Giant starts to eat the steel rail. During this scene you can see the distance of the railway sleepers changing from a fair distance apart to close together over the course of the shots. In the same scene you can also see that, although there is a crossing with lights, no vehicle could possibly pass as the rail has no crossover facility at that level. (00:24:30)
Factual error: In the opening short "Pikachu's Rescue Adventure" in the Bellossom song and dance scene a Poliwhirl calls itself a Poliwrath. This is obviously a mistake because of the body differences between the Pokemon.
Factual error: When the police arrive at the Little house to take the "missing person" report, their car has a blue light on top. Police in New York display red lights.
Other mistake: When the agent shows the spiral for the pattern of the messages, the spiral goes through South America and America. But the agent, before, showed two messages that aren't in the pattern; one in England (Stonehenge), the other in Cairo, Egypt.
Continuity mistake: When singing the song about what they would do if the monster came to their room in the night, Simon puts on Alvin's duvet/blanket as a cape. It then shows an imagination sequence where the blanket is a correctly sized cape to fit him. When it returns to the real world, the 'cape' is the size of his imaginary cape, nowhere near the size of the bed.Dan Moat
Continuity mistake: After the party, a girl with a maroon shirt and grey skirt runs out of the house twice.