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: 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.