Continuity mistake: If you look carefully at the monster (Frankenstein) you will see that his face is different in the ending scenes. The reason is, during the movie you see the monster take the woman doctor and throw her out the laboratory window. You then see the monster kind of stumble, which he really did and broke his ankle. So in the final scenes they replaced Lon Chaney Jr. as wolfman with a stuntman, and Lon Chaney Jr. finished the movie as the monster.
Continuity mistake: When we first see the baby bird in its nest at the beginning of the cartoon, you can see that the nest is positioned on a branch, but when we see the bird attempting to fly later on, the nest is now in the crook of two branches.
Continuity mistake: When the ant walks to the end of the cream pie and falls through some cream, you can see there is nothing around the pie. But a little later on, the pie is now surrounded by items from Donald's picnic.
Revealing mistake: When Tom is punctured in the rear by the fork that Nibbles is holding, his tail is missing.
Revealing mistake: When Mr. Peabody is fishing, it is obvious that he is in a boat on the floor of a studio. Rear-screen projection is used to show the ocean behind him, but while he is standing in the boat and trying to reel in his catch, the boat is absolutely motionless.
Continuity mistake: When the big dog points his gun towards the hole in the log, the length of the log changes between shots.
Continuity mistake: When Bugs says "Gin! You lose!" at the end of the card game, he is wearing a cowboy hat and gun holster, but when we see Bugs in the next shot, the hat and holster have gone.