Corrected entry: In the town meeting, the store owner talks about having so many microwave ovens stolen. Although microwave ovens were commercially available in 1979, they were not common at all. Even by the mid 1980s, only about 25 percent of American households had microwaves. So it's very unlikely that a small town hardware store would carry these - there just wouldn't be a market for it in 1979.
Corrected entry: In the scene with the Missing Dogs Board is shown, it includes a missing Puggle. The Puggle cross-breed was not created until the 1980s.
Corrected entry: When the evacuation siren goes off, the small spool of film is yanked off the feed spindle of the projector without first being rewound. All the footage they just viewed would have still been on the take-up spool at the other end of the projector.
Corrected entry: At the end of the movie, the locket flies out of the boys pocket. He should not even have had the locket because one of the soldiers took it from him when they were caught in the school. In the following scene in the bus, the soldier with the locket was taken by the alien.
Corrected entry: A character is seen building an Aurora Hunchback of Notre Dame glow in the dark model which is correct for 1979, but the model box is the "long box" used for the non-glow in the dark model in the sixties.
Corrected entry: Joe has a Space Shuttle poster on his bedroom wall, but the Space Shuttle program started in 1981, 2 years AFTER the film is supposed to have taken place.
Corrected entry: During a scene in Joel's room they show a model of the Space Shuttle and the external fuel tank is red/orange. This change did not occur until the 80's as a cost saving measure. Shuttle models before this had a white tank.
Corrected entry: In the scene where the water tower is attracting the metal and Joe's locket flies out of his pocket and he catches it, it opens and reveals the picture of Joe and his mother. The picture is flipped upside down.
Corrected entry: During a scene in Joe's room, a model of a TIE Bomber is seen. These did not appear until Episode V (The Empire Strikes Back), which was released about a year after the movie took place.