Deliberate mistake: When Saint is being dragged through the parking lot with all the exploding cars, there are a few shots where it is obviously just a dummy instead of John Travolta (the actor who played Saint).
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.
Deliberate mistake: Footage of Yugi playing at the Battle City Tournament is played across TV broadcasts around the world. However, the tournament footage is footage taken directly from the TV series, with some scenarios that were not filmed, and even the scenarios that were filmed feature camera angles and camera movements that would have been difficult to film. (00:05:27)
Deliberate mistake: When Brody confronts and then flees from the Headless Horseman, the horses never break into full gallop (it's little more than a stiff-legged canter), which is odd for a life-and-death chase with the bloodthirsty Headless Horseman in murderous pursuit. This was probably done on purpose, for safety reasons, since the actor playing Brody was performing his own stunt riding at night. To cinch the illusion of a real chase, audio was added of a 4-beat gallop.
Deliberate mistake: The music in the 50s wasn't, by far, the Shakira pop and hiphop style that the people dance to in the movie.
Deliberate mistake: In the unrated cut, when Jennifer/Tiffany is dragging the dead maid, you can see the "dead" maid is actually holding her head a few inches above the ground so her face doesn't rub on the floor. You can even see her subtly raise and lower her head as Jennifer/Tiffany grabs her and then stops.