Deliberate mistake: Polly's and Sky Captain's clothes are discarded because they are contaminated with uranium; however, Polly gets to keep her camera. Her camera would have been contaminated with uranium, too, because she had it with her in the underground cave.
Deliberate mistake: When Alice first fights the Nemesis, she attempts to jump over a fence and make an escape. When she lands on the police car, Nemesis fires his RPG at her. If you look closely, the rocket passes magically right through a chain link fence without touching it at all. (00:44:40)
Suggested correction: Rocket made a big hole in the mesh. Clearly shown.
Deliberate mistake: In the last shot of the movie, Alan Hackman looks at himself in a mirror through his own eyes. But when he looks away and runs off, the camera keeps watching the empty mirror in stead of watching what he sees. (01:26:25)
Deliberate mistake: In the Spanish version, the headlines of the newspapers are in Spanish, but the rest of the articles are in English. It helps supports the narration, but it causes a very weird effect.
Deliberate mistake: Perhaps to avoid getting an R rating or parental complaints notice how in the operating room massacre none of the doctors appear to bleed nor do Doc Ock's tentacles have blood on them.
Suggested correction: The problem is in both versions of the film, basically all of the deaths either happen off-camera, or are things like people being shocked to death or killed by being tossed around and presumably having their backs/necks broken. Most of the deaths would be bloodless or near-bloodless anyways, and the camera simply doesn't linger on the bodies enough to show any blood. This is also why the tentacles aren't really bloody. Sure, it was probably ratings-related, but it isn't technically a mistake.