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.
Audio problem: On the first level of the video game, after Velma brings up what she remembers what Eric said about the Scooby snacks in the game, you hear Daphne talking but you see Velma's lips moving. (00:01:00)
Factual error: In the beginning of the film, the Dowager Empress Marie states that the year is 1916 and that they are celebrating the 300th anniversary of their family's rule. The 300th anniversary actually took place in 1913. (00:01:05)
Continuity mistake: When Barry gets stuck inside for the first time, he hangs onto the drapes. His arm is straight across, but in the shot behind him, his arm is now bent and raised and above his head.
Other mistake: After Terrance shows the painting of Matilda and she runs off, if you keep an eye on Terrance as the screen pans upwards when there isn't a lot of his body left, he randomly disappears when the pigs appear in the shot.
Continuity mistake: At the beginning of the movie, Itchy comes to heaven in a teal colored shirt. When given a halo, he is in a blue shirt (the shirt is for heaven, but not given to him at that moment). When Itchy runs to Charlie right after that, his shirt is teal again. When Charlie tells Itchy he is dead, that's when the shirt changes to blue again (purposely).
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)
Deliberate mistake: Bowser has several teeth that appear and disappear throughout the movie. The best example of this is when Mario is trying to grab the Power Star. We see Bowser snarl at Mario before he picks him up. There is a gap between his two front teeth. However, when the scene cuts from Mario's horrified face to Bowser's face, there are now extra teeth inside that gap.
Continuity mistake: After the ball game, there is a cut over Miguel's eyebrow. Right after this scene, the cut has disappeared.
Deliberate mistake: In the scene where Emmet drives to work, you get Emmet's view of the dashboard with his hand switching on the radio. The car at that moment has no front window, perhaps to make the car look bigger from the inside. (00:04:50)
Continuity mistake: When the butler takes the mother and kittens to be abandoned in the countryside he is on a motorcycle and sidecar combination. During the trip the sidecar changes from one side of the bike to the other and back again. Also, when the sidecar separates from the motorcycle when the dogs are chasing Edgar, the wheel on the sidecar switches sides regularly as well.
Other mistake: During the Battle of Teth (the pillared jungle planet), the AT-TE's shoot the ledge at the top and there's not a single mark on the ledge afterwards, despite being hit with several joules worth of fire.
Continuity mistake: In the scene where Aladdin is talking to Jasmine in front of the mirror the jewelled flower is in a vase with a real flower when the monkey under the table takes the real flower and the scene cuts back and shows the vase with both flowers. Seconds later the vase is completely empty.
Deliberate mistake: When Tarzan fights with the leopard, it scratches his chest. However after they fall into the pit and Tarzan comes out carrying the dead leopard, the scratches on his chest have amazingly healed. [It is a long-standing Disney tradition that no evidence of violence is shown on screen. Still a mistake, but there's why].
Factual error: When hero boy and girl and Billy are on the runaway car at the north pole, they crash into the stopper at the end of the tracks. They are flung backwards when in reality, due to inertia, they should have been flung forward into the guard rail.
Plot hole: Johnny's dad jumps in his truck and gets to Johnny in moments. That same journey was shown to be an overnight bus journey for everyone else.
Factual error: The main character from the video game "Paperboy" is among the alien invaders in the final battle; since that game was first released in 1984, he shouldn't be there, because the probe the aliens received featuring video game footage was launched into space in 1982.
Factual error: When the minions are attempting to purchase tickets to get in to see/steal the crown, the admission prices on the wall are priced as £s and pence (decimal currency). As this was 1968, Britain was still using pre-decimal pounds, shillings and pence.
Continuity mistake: In the scene where Mindy is showing Spongebob and Patrick "Planktopolis," it shows a large fully-built statue of Plankton. A few seconds later the right side of the head is shown missing and still being worked on.