Factual error: Boon is using a payphone and behind him, at the left of the screen is the front end of a 'coffin-nosed' 1974-78 AMC Matador sedan, a car built a dozen-plus years after the events of the film. (01:18:10)
Factual error: After trying unsuccessfully to call Katie at the all-night cafe, Boone questions where she could be at six in the morning. The scene occurs during broad daylight. If the time were accurate, this could not be so, since it occurred in November. (01:18:30)
Factual error: When Karen Allen is in the kitchen she passes a fridge that has a Bicentennial sticker on it. The movie was set in 1962 and the Bicentennial didn't happen until 1976. (01:21:40)
Factual error: Listen to the crickets chirping at the football field where Larry and the Mayor's daughter make love. It's fall, everyone has jackets on. It's much too cold for crickets to chirp that rapidly. (Or at all at that time of year). (01:32:00)
Factual error: In the scene where Larry and the Mayor's daughter are on the football field, it appears to be artificial turf. Artificial turf wasn't invented until 1965, 3 years after the movie was to have taken place. (01:32:00)
Continuity mistake: When Stork and his associate step conspicuously onto the curb to watch the parade the pompom's yellow tassels face front. When the man behind them says, "Excuse me, my kid can't see," the purple tassels face front. (01:33:05)
Continuity mistake: During the parade scene at the end of the movie, there are shots of the street that it will take place on, and there is a view of a (misspelled) "Homestead Ferniture" store in two different shots. When the parade is actually taking place, the store is changed to (correctly spelled) "Homestead Furniture". Several shots after that, it changes back to "Homestead Ferniture" (01:33:20 - 01:44:00)
Revealing mistake: In the scene where the Mayor is giving his speech just before the parade begins, there is a man sitting in the bleachers behind him making bizarre faces and hilarious facial ticks in plain view of the camera. (01:34:05)
Continuity mistake: During the parade, we see Nedermeyer leading the ROTC cadets, who are carrying M1 rifles. Later, during the riot, we see Nedermeyer take an M1903 rifle off a cadet and use it to shoot at Flounder. (01:35:50 - 01:43:05)
Continuity mistake: After Stork pushes the drum major off camera to the right and seizes his baton, the scene cuts to a longer shot where he leads the band in the same direction. The drum major has disappeared. (01:36:30)
Continuity mistake: During the parade, Flounder dumps the bucket of marbles towards the camera, and they are all clear glass marbles. When the ROTC members slip and fall on them, the marbles are red, blue and yellow. (01:38:25)
Continuity mistake: The scene where Flounder tosses the box of marbles into the street to trip the ROTC cadets during the parade. Look at the background parade audience as they go into fast forward along with the action of the marbles... (01:38:30)
Continuity mistake: In the parade sequence only a few smoke sticks are shown to be shot into the crowds, but when the DeathMobile emerges through the smoke you can see dozens of billowing smoke sticks aligned across the ground. (01:39:20)
Continuity mistake: When the "Deathmobile" first appears, it spins around 180° and is parked parallel to the curb in front of the Beauty Bar (just past the grandstand) when Bluto pops out dressed as a pirate. When seen next it's now at a 45° angle facing the grandstand in front of the Fashion Store, but it was never heard or seen moving between shots. (01:39:55)
Visible crew/equipment: Near the end of the movie during the parade riot and Bluto is trying to escape, he jumps up on top of a building. You can see one of the uniformed soldiers bending down to give him help up onto the awning. (01:40:05)
Continuity mistake: At the parade, Bluto uses the banner to jump to the street. In the next shot the banner is intact again. (01:44:25)
Revealing mistake: When Bluto uses the banner to jump from the building, you can plainly see that his weight is being supported by a safety rope and NOT the banner itself, which is actually slack during the stunt. (01:48:25)
Factual error: At Professor Jennings' place, the stoned Boon and Katy sing "Hey Paula." The song was only pressed in November 1962 and didn't break into the charts nationally until late December of that year, whereas the scene depicted takes place sometime in the autumn of the same year, before the song would've even been recorded.
Continuity mistake: When Bluto is spying on the girls of the sorority house, all of the blinds are up giving him a good look. In the next shot when he moves the ladder to a nearby window, all of the blinds are down.
Factual error: When Larry and Kent first arrive at Delta house, and again after the new pledges are accepted, the Kingsmen version of "Louie Louie" is heard playing. This version was not recorded until April 1963, but the movie takes place in the autumn of 1962.
Suggested correction: Depending whether or not daylight savings time has ended at that point. If it has and the clocks are an hour earlier now, then it would be brighter by 6 a.m. then if they had not yet. There's no sun in the scene so this could explain it as a possibility.