When Humphrey Bogart is being bawled out by S.Z. Sakall, there is a light in the background that casts its shadow down into the word 'SILENCE.' In a few seconds, the shadow is some six inches higher and in a different position.
In one of the scenes, Eddie Cantor dressed as an American Indian, is being chased by other men dressed as American Indians, the film negative has been flipped; the signs on store windows are backward/mirror images.
When Tommy is on the phone then handing it to Farnsworth, the door is seen slightly opening then closing; apparently from the crew behind the scenes.