Revealing mistake: When Stan falls into the dug-out at the baseball game you can clearly see the crash mat that he lands on.
Revealing mistake: As the Wormwoods are driving out of the hospital parking lot at the beginning of the movie, the shot of the car driving from right to left has been flipped, as evident by the quick appearance of a hospital directory sign in the background being mirrored. (00:01:48)
Revealing mistake: In the mansion where the two flunkies are chasing the puppies that are to be skinned, one of them flies off the roof, through the stone battlements and crashes into a frozen pond. You can clearly see the stonework landing around him in the pond and bouncing/floating.
Revealing mistake: Throughout the movie the rescue helicopter changes. The paint job remains the same but they're two entirely different choppers. This can be most easily seen by the flat single-pane windshield of one and the round wrap-around windshield of the other.
Revealing mistake: When Hawkins is pulled into the lifeboat by Long John Silver, if you look closely, you will see that it is a stunt double who is doing the falling.
Revealing mistake: At the end, when the NYC children are rushing toward the peach to scoop out a piece to eat, you can see one little girl running with a piece of peach already in her hand.
Revealing mistake: Certain parts of this film were made during the spring months, not winter. In the background of the high up shots during the parade, leaves can be seen on trees (in the distance). Also, the grass is surprisingly very green, in several locations.
Revealing mistake: When Sassy comes out of the burning house carrying the kitten in her mouth you can tell that the kitten is fake.
Revealing mistake: At the start of the montage in which Frollo ransacks Paris for the gypsy girl, the shot of the three soldiers kicking down the baker's door very briefly places the more distant soldier off to the right "in front" of the closer central soldier; this is a case of incorrect animation cel layering.