Deliberate mistake: When Old Biff and Young Biff are sitting in Biff's car, the car's rear-view mirror vanishes during all shots of Old and Young Biffs together. Presumably this made the split-screen effect easier to do.
Deliberate mistake: During the ice storm, Hoke brings Miss Daisy coffee because he figured her stove was out. A few scenes before that they are frying chicken on a gas stove. Gas doesn't go out during power outages.
Deliberate mistake: The film uses Milwaukee County stadium,instead of Cleveland Stadium, as the home of the Indians. (00:26:10)