Deliberate mistake: The text the Master Control Program speaks in the human world is usually accompanied with a text projected on a computer screen. When Flynn attempts to hack into the system through the laser lab terminal, the Program is cut short at 'I'm afraid you.' (both on the screen and in speech) as Flynn progresses. In reality, however, it should be that the full text intended to be relayed by the MCP should be displayed on the screen, and only the speech gets interrupted. (00:29:40)
Deliberate mistake: In the finale, the main characters exit 'the fall' and climb up the outside of the vehicle. As the vehicle is travelling at thousands of miles an hour, they would have surely been sucked off instantly and most certainly would not have been able to maintain a grip on the ladder rungs as they climbed 'the fall'.
Deliberate mistake: The little red-haired girl boards a bus with other children who are headed to summer camp. As the bus drives away, there is nobody in the driver's seat. This movie maintains Charles Schulz's policy of never showing adults in his comic strips or animated television specials, but a bus driver could at least have been depicted in silhouette.
Deliberate mistake: When the villains rampage the White House, the flag's base remains on the ceiling, and the flag pole falls inside the house. So the final scene with Superman carrying the flag and its base as if it had been previously stolen or destroyed, is nonsensical, but it looks very patriotic indeed.
Deliberate mistake: One of Eva Marie Saint's lines in the dining car seduction scene was re-dubbed. She originally said, "I never make love on an empty stomach," but it was changed in post-production to "I never discuss love on an empty stomach." It is said that the censors felt the original version was too risqué.
Deliberate mistake: When Mr. Roboto is offering Austin a mushroom, the subtitles lead Austin to think Mr. Roboto is asking him to eat some shit, until Foxy reveals more of the subtitles to say "Please eat some shitake mushrooms." The correct spelling for this kind of mushroom is "shiitake." They had to cheat on the spelling in order to make the joke work.
Deliberate mistake: When the Dragon Emperor is giving his Terracotta army the speech near the end, you see a shot that pans across the faces of several of his soldiers. A few shots later, this exact same shot is played in reverse. It is very easy to tell if you look at the way the camera moves up and down to catch the different faces.