Character mistake: In the scene where Steve and Josie prepare to leave to fight the giant robot at the beginning of the movie, Steve tells Will "Oh, Will, a reminder: a lot of the kids at Sky High will only have one super hero parent, not two." When he says "one super hero parent", he holds up two fingers. When he says "not two", he holds up only one finger.
Other mistake: In the intro to the Pastoral Symphony, the narrator identifies the deity who cloaks the world with Night to be Morpheus, who is the Greek god of sleep and dreams. However, the character in the animation is fairly obviously female, with long hair, eye shadow, and lipstick. My theory is that the character was intended by the art team to be Nyx, the Greek goddess of Night. Night would be a more likely candidate to be making it nighttime across the world, while Morpheus would be more likely to put people to sleep or send them dreams.
Suggested correction: Without further evidence/proof, this theory remains just that. A theory.
Continuity mistake: When Kuzco and Yzma make a dive for the potion bottle, Yzma is turned into a cat simply by landing on the potion bottle. This suggests that a person only needs to touch the potion in order to be affected. However, when Kronk and Yzma are serving Kuzco dinner and are trying to avoid poisoning themselves, Kronk pours his potion drink on himself and is not affected.
Continuity mistake: When the law enforcement officer arrives, there is a tight close up on the handle of his .38 revolver. When one of the aliens scans his body, an image of a .45 1911 appears instead.
Deliberate mistake: When Eliza is about to be bathed, the mirror keeps turning around between shots to avoid reflecting the filming crew.
Other mistake: Two cars with the same license plate numbers are seen as the minions are hitch hiking on the road. The plates of the hippie wagon and the old lady's car both read D-6413.
Factual error: A toy modern four-door automobile and a clear plastic ball can be seen as the children play when the Burgermeister comes in on his wheelchair. Both unlikely for a story set (presumably) in the 1800's, at the latest.
Other mistake: When Nebbercracker is on the stretcher and is being wheeled away, the grass pulls off one of the last wheels. When the stretcher is loaded into the ambulance both of the back wheels are intact.
Continuity mistake: When Larry and Nick Daley first enter the British Museum, Nick takes his beanie off twice, in consecutive shots.
Factual error: In "Pikachu and Pichu," when Pikachu and the Pichu brothers come to the big play structure thing, there are a bunch of Pokemon around, including a red-and-white, ball-shaped Pokemon called Voltorb. The dubbers for the English version made a very noticeable error here: instead of Voltorb saying "Voltorb," (almost all Pokemon say parts of their names when they speak) it says "Electrode," which is the name of a similar-looking, but different Pokemon. The two are both red and white, but the difference is that Voltorb has eyes on the red part of its body, while Electrode has eyes on the white part of its body.
Continuity mistake: The boys go out in their boat to water ski, only to find that Jones has built a huge dock that blocks their way. No matter. The boat does not contain skis nor a tow-rope anyway....
Visible crew/equipment: In the fight scene on the stairs near the end of the movie, the camera shot looks up and there is a security camera mounted up in the corner. (01:33:34)
Plot hole: During the scene where Merida gives her speech on "breaking tradition", her mother, as a bear, moves silently behind the majority of the crowd, so they don't see her. Fair enough. However, Merida and her father's clan are all looking in the same general direction (towards the crowd) while she's speaking - how does no one from Merida's clan see a bear moving at the back of the room?
Continuity mistake: When Juni handcuffs the metal box to his wrist, it switches back forth from his right wrist to his left over and over again. (00:35:05)
Visible crew/equipment: When Shane is talking to Mrs. Plummer before she leaves, throughout the scene the camera man is reflected in her window (he is in black, not to get confused with Shane's white shirt) and as the car drives away the camera is shown backing up in the black door.
Continuity mistake: In the scene where the security guard halts Mr Bean (dressed as a grandma) and the supposed kidnapped child, he is asked for his pass. Mr Bean hands the guard an already opened ID style flip card, but when the guard takes it, he is seen opening it as if it were closed.
Plot hole: Joy and Sadness are stuck outside of the control center. They are trying to figure out how to get back, and encounter maintenance workers who are discarding old memories. The maintenance workers show that they have the power to send memories back up to the control center to be played. Why couldn't they send the core memories that Joy had back up the same way? Better yet, why not use that method to send Joy and Sadness back up to the control center? The director of the film is even aware of the plot hole, and said "Yeah, well then we wouldn't have a third act," before explaining how the idea of recalling memories was added in later, "box[ing] [the screenwriters] in a corner a little bit."
Continuity mistake: When the evil king's female assistant is "turned into" Odette, and Prince Derek is dancing with her near the end, he puts the locket on her. The chain goes around her hair, and in the next shot, it's under her hair. They were dancing the whole time, so how could she or Derek have pulled her hair out of the chain?
Revealing mistake: When the kids step out of the water and walk towards the house, the floor is already soaking wet from previous takes.
Audio problem: During the Tea Party scene, the Mad Hatter and March Hare ask Alice to tell her story. After the Mad Hatter says "And when you come to the end, stop!" audio follows of the voice director saying "great," leftover from the original recording. (00:45:40)