Revealing mistake: In "Wonderful, Wonderful Day" there are live birds flying on the set, but they were confused by the backdrop and several crash into it. (The director acknowledges this in a documentary.)
Revealing mistake: In the scene near the end when water is filling up the submarine, Kirk Douglas begins fighting with a member of the crew to escape. As Douglas hits him his false sideburn falls off and flies across the screen.
Revealing mistake: When we first see Yosemite Sam at the tiller at the beginning of the cartoon, he moves the wheel back and forth but the capstan and rope do not move even though they are meant to be attached to the wheel.