Continuity mistake: In the exterior front shots of Elliott's house there are some significant changes to the landscape in different shots. For instance, the two lampposts at the bottom of the driveway change to an entirely different style in some shots, and the huge garden boulders repeatedly vanish and reappear. Also, note when Michael takes off on Elliott's bike to go search for ET, the in-ground lamppost that should be beside the mailbox has vanished, but it reappears when all the government agents are setting things up outside the house.
Continuity mistake: When the twins are singing about Brad for the talent show, and Michael was playing the piano (you have to listen and watch), his hands are suppose to go across the keys but he is still doing the fake up-and-down-hand-move.
Continuity mistake: When De Niro's character gets in the limousine with Lewis' character he has a hurt hand. He wraps it with a handkerchief. As the scene progresses the handkerchief disappears and reappears depending on the camera angle. (00:07:15)
Continuity mistake: The woman reporter was walking behind Gandhi at the beginning of the movie. At the end, in the "repeat," she wasn't.
Continuity mistake: When Dustin Hoffman (dressed as Dorothy) goes to babysit for Jessica Lange he takes a bunch of flowers as a present. Jessica Lange takes them from him and throws them on the kitchen table. Then she walks into the kitchen (shot from different angle) still holding the flowers and throws them on the table (again).
Continuity mistake: The sequence in which Dragon is chasing Mrs. Brisby through the field, up the tree and eventually into the mill's lake, watch his eyes. The original placement is (from viewer's perspective) blue on the right and gold on the left. When he chases her up the tree the gold one is visible on the right, it then switches back when the camera cuts back to a wide shot. This happens again a few seconds later near the lake.
Continuity mistake: At one point in the film, the wingspan of Q is mentioned. Later on, its length is mentioned. The monster is twenty feet longer than its wingspan.
Continuity mistake: Near the end of the film when Jessica Lange, playing Frances Farmer, runs away from her parents' home in Seattle, Washington and takes on the life of a vagrant. She is seen hitchhiking on a road, which is obviously adjacent to a desert and looks very much like southern California. When the police pick her up and drive her back home, in what seems like a short period of time, she is transported back to the Seattle landscape surrounding her parents' home.