The rifle Race carries on the first expedition to track the monster is missing when Race calls out hello in the second village.
The Monster's progress is far slower when it's depicted at ground level than when it's seen from above, moving at a very rapid pace.
When Jonny snatches Bandit from the monster's path, the monster is almost touching the spot where the dog was hiding, which was in the middle of the clearing around the lab compound. In the next shot of the monster's advance, it's back in the jungle.
In the final scenes, the monster's size appears to vary from about a man's height to three times taller.
In the second village, Jonny stands between Hadji and Race, but when they take off in their jet packs, Jonny and Hadji's positions have switched, putting Hadji in the middle.
Dr. Quest flies the jet plane this time, but as they leave Cave Island, Race suddenly appears in the pilot seat during the close-up delivery of his last line.
When Race first switches on his jet pack, the exhaust is seen in front of him instead of behind him.
When the Quests are armed with paint bombs, Race is in the foreground of the shot. Dr. Quest's jet pack exhaust is seen in front of Race when it should be behind him partially blocked by Race's right arm.
When Race and Benton throw paint bombs at the monster, Benton throws his pink paint bomb three seconds before Race throws his blue paint bomb, but it's Race's blue paint bomb that hits the target three seconds ahead of Benton's.
When Bandit chases after Dr. Quest flying off to bait the monster, Jonny's mouth doesn't move when he calls after Bandit.