The Invisible Man (1933)

Revealing mistake: When the woman at the bar brings Jack the mustard which she forgot, Jack puts his napkin in front of his mouth. A fraction of a second before that, you can see the down-side of his face which should be invisible. Instead of nothingness you see it's all black. That is material used for the special effects, but they didn't 'make it invisible'. (00:06:50)

Other mistake: At the end when the naked but invisible hero runs from the police but is given away by his footprints in the snow, the footprints are of shoes, not bare feet.

Revealing mistake: When Jack steals the bike he's supposedly riding it but you can see a rail on the ground.

oswal13

Trivia: A purely technical error with all "invisible man/woman/boy" movies is that the eye works by interacting with light incident upon the retina. The Invisible Man is made so by being rendered transparent to visible light. This means that his eyes no longer interact with light - so he ought to be completely blind. (However, a healthy suspension of disbelief makes for a great story.).

Trivia: Claude Rains' real face is only visible for about 20 seconds in the last scene of the film.

The Invisible Man: The drugs I took seemed to light up my brain. Suddenly I realised the power I held, the power to rule, to make the world grovel at my feet.

The Invisible Man: And if you try and escape by the window, I shall follow you, and no-one in the world can save you.

The Invisible Man: We'll begin with a reign of terror, a few murders here and there, murders of great men, murders of little men - well, just to show we make no distinction. I might even wreck a train or two... just these fingers around a signalman's throat, that's all.