Revealing mistake: Most of the posed, fake displays in the ape's Museum of Natural History contain real people who are slightly moving if one pays careful attention. Especially noticeable are those posing with objects held in - or above - their hands.
Revealing mistake: When you see the first shot of the dead Mercutio, he's still breathing.
Revealing mistake: During the bank hold-up at the beginning of the film, one of the pushes a man on the wall. It wobbles like cardboard.
Revealing mistake: Rosemary crosses 5th Avenue as she goes looking for a bookstore to find more material on witches and a lot of bystanders can be seen staring at the film crew. (01:36:10)
Revealing mistake: When we first see Oliver Reed, we see his shadow first on the wall at a ramp to the pub. As his shadow spreads its legs, we then see him spreading his legs a moment later. Shadow puppetry was used by the director to give the audience the impression that he is ominous and foreboding before we ever see the man himself. (00:54:10)