Continuity mistake: When Jerry appears from the hair of the toy lion, you can see that behind him there is a decoration and some purple baubles. In the next shot, the decoration has disappeared and the baubles are now much closer to the lion.
Continuity mistake: When we see from Tom's view the fridge he is going to crash into, you can see the cheese is on the second shelf, but when he crashes into the fridge, it has moved to the top shelf.
Continuity mistake: When Porky slams the window after seeing Rover on the ledge, you can see the window has nothing on it. But when Porky turns around and sees Rover about to fall over the edge, a catch suddenly appears.
Continuity mistake: When Bugs puts up a "Camp Here" sign near his hole, you can see there is nothing behind the sign, but in the next shot a tree has suddenly appeared.