Revealing mistake: In the David Letterman scenes, Paul Schaeffer's head is shaved, which he just did recently (maybe within the last year to year and a half). (01:15:00)
Continuity mistake: When Kelly is on the boat with Hank and the soon to be headless deputy, her green vest (life-jacket) is fully unzipped. When we see her immediately after she's been knocked in the water, her jacket is zipped almost all the way up.
Continuity mistake: When Frankie is about to receive the first stigmata (when sitting in the bath), a pigeon suddenly flies up. When she takes a piece of a feather that flew into the water, you can already see stigmata marks on her right-hand wrists.
Visible crew/equipment: When Jim West is hanging by the rains of the horse you can see the rider's boot as Jim West is telling the horses to back up.
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 Lance arrives at the church to call off the wedding, he exits an old model cab with a square body. As he's walking up the church stairs the cab pulls off and is a newer model.
Continuity mistake: The bottle of Peach Schnapps that Trip (Josh Hartnett) brings to the dance is alternately full and half empty during the scene. When Trip pulls it out, it is new and unopened. He hands it to Lux to drink, at which time it is nearly empty. He then drinks from it, and it is about half-full. He next hands it to the other couple, at which time the bottle is nearly full again. (00:57:56)
Continuity mistake: When she goes through the lasers it takes 2 minutes to get to the mask, but it only takes 30 seconds to get back.
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)
Revealing mistake: When the house has been locked down at the beginning of the film no moonlight could come in, however when the guests are being shown the coffin with the guns in there is a shaft of bright moonlight shining on to it.
Continuity mistake: In the scene where the pet shop girl reaches into the aquarium, clearly the whole chest part of her shirt is submerged in the water. When it cuts to her at the counter only the area around her nipples is wet.
Visible crew/equipment: When Homer follows Rose Rose inside after finding out she's pregnant, there is a visible "T" taped on the floor for him to stand on.