Best animated movie mistakes of 1942
Continuity mistake: When Daffy hands Porky a shotgun, he says "It ain't gonna do you any good!" and pulls down a sign saying "Duck Season Opens Today!" You can see that the sign has a cord at the bottom of it and an exclamation mark, but when we see Daffy walking back from Porky a few shots later, the cord and exclamation mark have both disappeared.
Continuity mistake: When Jerry runs onto the record player, he runs next to a button panel and there are four buttons on it: Fast, Stop, Start and Change. But when he is pressing random buttons later on in the cartoon, a "Record" button has been added and the "Change" button has disappeared.