Continuity: The score in the "Pong" game between the scientist and the monkey.
Continuity: The sheriff's police cruiser switches from a 1973 Plymouth Satellite Custom to a 1973 Dodge Coronet where Frady takes a shortcut through a construction site. And when he crashes the cop car in a local Safeway, the cop cruiser is a 1973 Plymouth.
Revealing mistakes: During the chase, right up until Joseph Frady crashes his stolen police car, the driver of his car is wearing a wide-brimmed sheriff's hat. He crashes with the hat, but gets out of the car hat-less.
Factual errors: In the opening Independence Day parade sequence, there are no leaves on the tree branches visible as the senator and his wife pass by, but the leaves would be full and green on July 4th in Seattle.