Factual error: Gallaxhar scans the galaxy to find the missing quantonium. The scanner zooms in on earth, showing it to be very close to the center of the galaxy. Earth is actually nowhere near the center of the galaxy; it's located much closer to the outer edge.
Factual error: After trying to get his balloon back, Carl Jr. falls and breaks his arm. The ambulance that picks him up has a modern-day electronic siren, when in the 30's it would be a mechanical siren and would be much smaller.
Factual error: In the credits, Josh Peck is said to voice Rudy. He actually voiced Eddie.
Factual error: The alligator mentions wanting a Bananas Foster. This dessert was invented in 1951 but this movie takes place in 1926.
Factual error: When the super-scrambled monster is destroying the town, everything it destroys falls down completely, despite the fact the monster only hits one side of it. (01:00:15 - 01:04:40)
Factual error: At the beginning Scrooge is seen signing Jacob Marley's death certificate in the year 1836. English Birth, Marriage & Death certificates didn't come into being until 1837.
Factual error: When we first see Rat, he's noticeably taller than Mr. Fox in a close-up. Shouldn't it be the other way around?
Factual error: The lead song, "Lollipop," wasn't written until 1958, seven years beyond the chronological order of the movie.
Factual error: Leo says he smells potato, but he is in a space suit and in space, making it impossible for him to smell it. (00:33:00)