Continuity mistake: When the two men talk in the tent at the beginning, watch when one turns around - there is a clear cut in mid action where the men's positions change without any movement. (00:13:05)
Visible crew/equipment: When Dr Moreau is showing Parker his plant experiments there is a moment, just after Moreau says "That's one there", when the camera moves past a pillar and the shadow of some equipment is cast on the pillar. (00:30:28)