Gary repeatedly refers to the gun as a revolver, yet it has no cylinder. Later, he loads a magazine into it, proving it is not a revolver.
Close-up shots of Gary as a spider often show him surrounded by plants, even when long shots show him in an open space.
The plane that takes off is a completely different make than the one that crashes.
Soon after takeoff, the plane's prop spinner changes from rectangular to conical.
When Gary goes through the jungle with the girls, his shirt is ripped. When they arrive at the cabin, the shirt is not ripped.
At 9 minutes in the plane takes off as a twin engine Convair CV 240. In the air it is a four engine Douglas DC-4.
From Los Angeles, the dancers stop in New York City on the way to Singapore.
In long shots near the end of the movie, Gary is not wearing his spider make-up.
When Mike Blackwood is talking about the plane crash on the phone, he smokes an unlit cigarette.
After Gary kills Linda, her head is underwater in the close-up, but above water in the long shot.
When Joe finds Bob dead by the tree, the surrounding area is pitch black. The previous and next shots had plenty of light.