Revealing mistake: When O'Keefe takes his bride-to-be Dolaroo to Hong Kong to be married, a 1950's truck goes past in the background. Unfortunately, the film is set in 1870.
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: In the shot of the helicopter hovering above the apartment building, the blue screen technique is needlessly revealed by the eratic and physically impossible movements of the chopper. This could have been avoided if the camera shooting the aircraft had been stationary. It appears, however, that it was a handheld shot.
Revealing mistake: When Bob and Ben prepare to gas the ant nest, an ant appears below them. But its legs move too slowly, compared to the speed in which it appears; it rather looks like it is driving across the ground on (hidden) wheels.
Revealing mistake: Just before Anthony Dawson is going to be stabbed to death by Grace Kelly with a pair of scissors, you can see for a very short moment that the scissors are already attached to his back.
Revealing mistake: When Kikuchiyo tricks and kills the gunner, he chases him a short way, then stabs him with a sword. Even though there's a tree blocking the action, you can still see he never actually stabs him, he just lightly stabs the ground near him.
Revealing mistake: When the heroine sees the creature emerge from the cave and strangle the man she was with, she hams up her acting in the worst, most blatant way - she throws herself to the ground, screaming. She didn't even make it seem like she tripped or anything.
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.
Revealing mistake: Many of the cavalry soldiers were carrying M-1 Garand rifles (WW2 era rifles).