Continuity mistake: Darth Maul's neck is black, but when he is talking to Darth Sidious on Coruscant, his neck is flesh-toned. (00:38:45)
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.
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.
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 Interceptor team flies in their cargo plane to Mexico to investigate the UFO crash, several shots filmed from the front show the six of them all in the cockpit (not in the body of the plane.) They're seated as they might be in a car, three across, front and back. The window of the cockpit looks remarkably similar to a station wagon windshield, down to the large rectangular front windshield, and even the rear view mirror is in place.
Continuity mistake: At the end of the movie, when Portia and Andrew are lying in their "beds," they are holding hands. In all of the far away shots, Andrew's hand is on top, but in the close shots, it is underneath. (01:59:20)
Continuity mistake: Just as the final fight between Luc and Seth is about to begin, three computer panels are shown to display Seth's different approaches to crack the code he requires to survive. While the two LCDs to the left and right have the output of a brute-force algorithm simply guessing all possible combinations for the code, the CRT-monitor in the middle shows Luc's severely injured daughter which Seth offered to heal in exchange for Luc telling him the code. However, if you have a closer look at the screen it states "HEALING COMPLETE" (even with a blinking frame around it), although close-ups of the "Rejuvo-booth program" before (e.g. at 1:08:00) and after (e.g. at 1:09:24) this shot claim it to be "INCOMPLETE". (01:08:55)
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: At the very beginning of the film we see the Seminar Leader start to write eXistenZ on the board. We see him write the letter 'e', but then the camera changes and he starts to write the letter 'X'. Notice that the letter 'e' has changed from how he originally wrote it. Then when he finishes writing eXistanZ the camera switches position again and the writing has all changed the look again. Most noticeable by the crossing of the letter 't'. As we saw him write it, then cross portion was much higher than in the wider shot.
Continuity mistake: After the party, a girl with a maroon shirt and grey skirt runs out of the house twice.
Continuity mistake: After Hall has been shot in the leg in the simulation of LA 1937 the hole in his trousers and his injury disappear, as seen in the fight sequence at the pool. Hall even uses his leg to hit the bartender in the stomach, what would have made this very painful if he had been shot there.
Audio problem: When Alex is appointed head of Netforce, he looks down for a moment and says, "I don't know what to say." And then looks back up. His mouth is in clear view the full shot, yet never moves once during this line and is completely shut. The audio was just dubbed over the footage in post. (00:23:25)