Factual error: At the very end of the movie, Ray is telling Louis about the Tunguska Blast of 1909, but the famous blast actually occurred in 1908. Given his oft-demonstrated levels of knowledge, he'd know better. (01:37:38)
Factual error: For a movie supposedly set in late December in a Northern state, all of the deciduous trees still have leaves on them. The most obvious place to see this is in the opening scene, when Billy is trying to start his car in front of his house. (00:07:05)
Factual error: When Axel and Taggart are taken under fire by the gunner with the dark glasses (who is shot by Billy), notice that the gunner stands perpendicular (i.e. at a 90° angle) to the stairs where Axel and Taggart take cover. Yet, two of the bullet holes appear in a column at the base of the stairs which would have come from a different trajectory, namely in line with the stairway and thus from Axel and Taggart's flank.
Factual error: In the scene where Derek Smalls is having trouble with the airport security the gate only beeps when he walks 'in'. The gate would beep no matter what way he walked through it. (00:41:00)
Factual error: When the crowd and sheriff are waiting at the GA/TN state line we see a road sign that says GA. Hwy 16. GA. Hwy 16 runs east to west (Tennesee is north of Georgia) and is approximately 150 miles south of the state line. (01:34:45)
Factual error: When Rob Lowe first arrives in Oxford he is driving down a street taking in the sights. Most of the sights he views are actually scattered throughout the town and not on any one street. This is especially true for Radcliffe Camera (part of the Bodlean Library) as it is in a cobblestone courtyard completely surrounded by buildings and cannot be viewed from any street.
Factual error: When the TV store is closing at Bloomingdale's, The Richard Simmons Show is shown on the monitors. In 1984, when the film is set, this show was broadcast only in the morning and was not released in syndication. The show would therefore not have been playing on a television channel in New York City in the late evening.
Factual error: None of the "Colombians" speaks with a Colombian accent or uses Colombian slang.
Factual error: In the scene with Tempest (the video game in the cinema's foyer), Regina is annoyed to find the tag 'DMK' shown in the scoreboard, which she otherwise dominates, and she sets out to remove it. After completing a game which scores higher than 'DMK', she overwrites his name on the scoreboard and her name is both above and below. If this had been a real video game, his score wouldn't have been removed from the list, it would have just dropped down one place. She would have needed to play several games, bettering the 'DMK' score every time in order to own the board again. She would just keep knocking DMK down the list, she could only overwrite the last place.