Revealing mistake: During Fritz's fight with the giant anaconda in the swamp, James MacArthur's stunt double becomes apparent by virtue of a bald spot showing on the back of his head. (01:10:30)
Revealing mistake: Chapter 3: Walking Bombs and Chapter 4: The Destroying Ray. They accelerated the movie when you see the robots, or walking bombs, to give the illusion of mechanical movements. The only problem is that when you see people fighting with them, their movements are also accelerated.