Continuity mistake: When Jerry launches his egg carton, there are initially three light bulbs in the back, but when he releases the bulbs, there are now four.
Continuity mistake: When Droopy is standing the door, he tells the convict he's going to call the cops. At this point you can see there is nothing next to Droopy on the frame, but in the very next shot a hinge has appeared.
Continuity mistake: When Bugs sees the finish line, you can see there is nothing on the road and nothing by the finish post. But when Bugs approaches the finish, there is now a line on the road and the post is in front of a tree.
Revealing mistake: When the mice are feeding the cat, the cat sits up and a mouse passes through his head.
Continuity mistake: When we see Mr Meek with his axe at the beginning of cartoon, you can see there is nothing in the fence beside him, but in the next shot, wire fencing has suddenly appeared.
Continuity mistake: When Daffy gives Porky his card, Porky holds it with both hands but a close-up of the card shows him holding it with only one hand.