Continuity mistake: When Sylvester discovers that the cupboard door has a lock on it at the end of the cartoon, he is holding a can opener in his right hand, but after we see a close-up of the lock, we return to Sylvester and the can opener has disappeared.
Continuity mistake: When Spike grabs the bomb (painted as an apple) from the cockerel, he takes a bite out of it. You can see that when Spike is about to eat it, the eaten part of the bomb is facing his mouth, but in the next shot the eaten part is now facing downwards.
Continuity mistake: When Bugs is making Francois look like a rabbit, he cuts up Francois' moustache to make whiskers. When Bugs says "You make a swell rabbit, Doc!" the whiskers disappear.