Continuity mistake: When the sword act performer waits for his subject to appear from the audience, there is a shadow behind him on the curtain. In the next shot, there is no shadow.
Continuity mistake: During the Blue Birds in the Moonlight song you can see Gulliver holding his drink. In the next shot while he's laughing the drink has disappeared.
Continuity mistake: When Casper the Caveman takes off his caveman's outfit to go swimming, he puts his outfit near the edge of the bank. After Daffy says that he can't swim, he reverses back onto the land and goes and collects his suit, but this time the suit is now much further away from the bank.