Revealing mistake: When George and the young man are in the garden, telling jokes and drinking bourbon, the young man pours some bourbon into George's glass, but the bourbon, instead of being brown, is clear, like water.
Revealing mistake: A safety wire is visible as Grandpa hits the low tree branch that knocks him off his horse.
Revealing mistake: When the workers are running away from the mine before it explodes, one of the female extras (the woman wearing the blue shawl) suddenly slows down to a relaxed stroll - obviously thinking she's safely out of shot.
Revealing mistake: The zombie of John Martinus throws the lifeless body of Alice from the tin mine pit head onto the ground. When Sylvia examines the body after, Alice very obviously blinks. Visible at normal speed, but easier to see slowed down.
Revealing mistake: When the US Navy engages the enemy at the blockade on the Yangtze River, during combat scenes, a sailor's (prop) bayonet wiggles on board the San Pablo.
Revealing mistake: At the Halloween Party, a girl with a green dress says to Charlie Brown, "Charlie Brown, you'll have to model for us." When she says this, she suddenly grows a third hand, then she has two hands again a little later.