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.
Revealing mistake: At the beginning of the Purple Death segment, a policeman checks one of the person that died of the Purple Death. The "dead" man moves his eyes.