The leopard jumps off the tree in the dark but when the obviously dummy leopard lands on his victim, it is light.
Stock footage from African and New Guinea natives are mixed.
At the end of Chapter 2 when the ape man is on board the ship, he holds Nora lane horizontally and throws her out of frame. As she was thrown horizontally, it is physically impossible for her to land standing up against the cabin door.
Chapter 10: The man in dark gasses knocks Tom out and drags him out of sight, but, in Chapter 11 he knocks Tom out and picks him up.
Chapter 11: As the man in dark glasses picks Tom up, Tom throws his left arm around his neck.
There is a physical difference between "Mrs. Colby" and the "Man with the dark glasses." The "Man with the dark glasses" is taller and fuller of figure.
When the ape man grabs one of the natives' spears and throws it back at him, the audience can clearly see the shaft is between his rib and arm, and it drops to the ground as he falls, clearly not having penetrated him.
In Chapter 12, when Grant is escaping from the natives, you can hear one of the natives say; "What's going on?" among all the native grunting.
The same two natives are shown being shot and killed in two different chapters by two different people.
Cyril Wainwright shows up alive with his right arm in a sling in Chapter 12. But he was killed in a earlier chapter. The Police Inspector even put Peterson in jail for his murder.