Continuity mistake: When the mice are serving the cat, there is a mouse who is taking the cat's order and he drops his notepad on the floor when he says "Mouse?" and runs off. But when we see a full view of the cat and the mice in the next shot, the notepad is nowhere to be seen.
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.
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 is viewing footage of the previous encounter between Cecil Turtle and himself at the start of the cartoon, you can see that viewed from behind, the projector only has one reel. When we see Bugs eating his carrot in the next shot, there are now two reels.