Continuity: Teddy disappears from the dinner table between shots.
Continuity: One of the boys gets out of the swimming pool twice in different shots.
Audio/visual unsynchronized: When Henry asks David why he was going to cut Monica's hair.
Continuity: When the robots open the frozen door to the Amphib Craft, David's trousers are already wet on the left leg from the knee down. But when he gets out, they are dry and twice he slips on the ice and both times he lands on his left knee.
Continuity: When Dr. Hobby removes the CPU from mecha Sheila's forehead, the module is about as big as a walnut. But when he holds the module up to show to his colleagues, it is a cube about the size of a billiard ball.
Continuity: When we see the chef mecha scavenging for a new eye, he has no hat. But when we see him again in the cage, his hat is clearly a permanent part of his head.
Factual errors: The Yeats poem is misquoted on the door in Dr. Hobby's office. Dr. Know reads it "Come away, O human child! To the waters and the wild...” This is the correct line, and also what Gigolo Joe says as he reads it. However, the lines on the door read "To the waters of the wild".
Continuity: When David meets Monica, he enters the room and stops. He is then instantly on the other side of the room, facing the window, and must turn around before speaking for the first time.
Errors in geography: Much of the film's early action takes place in Haddonfield, New Jersey. New York City is subsequently shown to be under water. Haddonfield's elevation (81 feet) is lower than that of New York City (87 feet), and it is near both the Atlantic coast and a river leading to the ocean, so Haddonfield should be under water too.
Revealing mistakes: The Swintons live in New Jersey, but Martin's prescription bottle is from a Los Angeles pharmacy. (This is visible briefly when the spinning turntable stops and before the bottle is picked up.)
Factual errors: The story opens with New York and other coastal cities having been flooded due to the melting of the polar ice, but the ending has the world in the midst of an ice age. If that were the case, the waters would have first receded, leaving the cities on dry ground again. In fact, sea levels would have dropped even further than they are today, as more and more water was bound up in the ice.
Continuity: When David approaches Monica's bed to cut off a strand of her hair, she is first lying her face turned away from him. In the next shot, she is lying face towards him.
Continuity: When David picks up the lamp and swings at his other self, he swings right handed but it shows him swinging left handed.
Continuity: When Monica reads the notes that David has written, the number of pages in her hand change between shots.