Revealing mistake: In the last third of the film just after the announcement that Kong is coming, a native jumps out of his hut, loses his balance and falls by a chicken coop. His wig comes off and gets caught on the fence.
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)
Revealing mistake: When Pinky runs into the mirror, causing it to shatter, you can that the mirror does not shatter until Pinky falls onto the floor.
Revealing mistake: At the beginning of the movie when he is talking to the figure of Marie Antoinette if you look really carefully you can see the actress who's portraying her ever so slightly move.
Revealing mistake: In an overhead view of Oliver Hardy going down the sawdust chute, you can see it is a stunt double.
Revealing mistake: When Denham is rowing the boat to the island - an obvious rear projection - the oars never touch the water.