Revealing mistake: In this scene we see Cheetah jumping down from a tree to the ground. In the next shot we see Cheetah and a circle of light moves, which indicates they were using a mirror or even a light for extra lighting to brighten up the shot. This happens very briefly and is very noticeable.
Revealing mistake: In the scene where a British soldier (Williams) and Sgt. Joe Gunn (Humphrey Bogart) are in a trench, the British soldier is shot dead by a German sniper. Joe Gunn moves in for a closer look and it can be seen that the "dead" soldier is breathing, his shoulder is moving. (01:15:30)
Revealing mistake: When the mice are feeding the cat, the cat sits up and a mouse passes through his head.