Factual error: The aliens request a meeting with Dr. Marvin on the shores of the Chesapeake Bay, near Washington DC. However, the shot of him driving along the shore line shows mountains in the background, which don't exist in Eastern Maryland. (00:35:13)
Factual error: During the meeting concerning Godzilla, one of the scientists incorrectly states that the Jurassic Period was 2 million years ago. The Jurassic Period lasted from 180 to 135 million years ago. (00:29:40)