Factual error: Tommy is wearing a Hulkamania shirt while the band is being assembled together. The band was formed in 1981. Hulkamania didn't start until 1984.
Factual error: The film is set in 1987 but most of the street lights seen throughout the movie are LED street lights and some high pressure sodium Philips lanterns (produced from the early 1990s to early 2000s), neither of which were around back then. Similarly many of the shots of the M1 motorway show modern cars and smart motorway/variable speed limits, which never existed at the time.
Factual error: The American soldier on the balcony is waving a 50 star flag. (01:30:06)
Factual error: There's a flashback to 1989 in an arcade and we see Mortal Kombat and Mortal Kombat II there. The original wasn't released until 1992, and the sequel in 1993.
Factual error: Towards the end, Quinn injects herself with a syringe full of Morphine to try and kill herself. She's dead in seconds. This does not act nearly that fast. Especially from injecting it in her arm.
Factual error: Like so many other films that take place underwater, this one makes the mistake of having characters who can hear each other underwater despite not wearing earpieces and having their ears exposed to the water.
Factual error: When they first get attacked in the mini van, the side windows crack and get scratches. (You can see the "spider webbing"). A side window shatters in small pieces when they crack slightly.
Factual error: At the end of the movie, Effie comes out with two AA-12s. As she fires these guns, they have the sound, effects, and firing pattern of an assault rifle. These two guns are shotguns, not machine guns. (01:13:00)
Factual error: Alec Baldwin opens a pack of Chesterfield cigarettes and they have a filter. This is in the late 50's - Chesterfields did not have filters until 1966.
Factual error: When the teacher announces they are going to Prague, they basically walk around the corner to a waiting bus. This is impossible because the part of Venice they are in is inaccessible to motor vehicles.
Factual error: Dr. Fielding is dead inside the JPL building. His blood is dripping onto a telegraph key and it is sending perfectly comprehensive Morse Code. The blood drips are too random to do that. (01:13:25)
Suggested correction: It's clear he was alive at one point, and the way he has positioned shows he was probably already sending that. There was a break from him sending it, and it's clear the kids didn't understand the morse code, which could be the point his blood was dripping.
That could be. OK.
Factual error: With a number of flowers blooming, the movie appears take place in spring. There are many scenes of central park with flowering trees and shrubs in full bloom. However, the yellow blooming shrubs called forsythia do not bloom at the same time as the flowering cherry trees. Forsythias bloom about a month earlier than cherries and are usually the first items to bloom in spring.
Factual error: The scenes set at Wrestlemania XXX (2014) were filmed at a RAW show in 2018 - fans are visible in the background wearing wrestling merchandise more recent than 2014.
Factual error: The scene where Pluto gets burned takes place at the Santa Cruz Natural History Museum, directly east of the Beach Boardwalk. In order to drive to the boardwalk in the scene immediately afterward, the Wilsons would have to pass through the line of Tethers holding hands.
Factual error: As well as the sergeant's stripes on his cuff, Sergeant O'Neil wears three pips on his epaulettes, which would indicate a much more senior rank and would not be worn together with the stripes.
Factual error: When we see Elton John's father Stanley in RAF uniform at the beginning of the film he is wearing other ranks' uniform. Stanley was commissioned in 1944, three years before Elton was born, and served as a commissioned officer until his retirement as a squadron leader in 1963. He should be wearing officer's uniform.
Factual error: Pope Benedict and Cardinal Jorge Bergoglio are hanging out in the room by the Sistine Chapel having a pizza and a drink together. The drink of choice is Fanta, apparently Joseph Ratzinger's favourite beverage. The scene is supposed to happen in 2012, but the label of the bottle is a more modern one, introduced in 2016. (01:34:20)
Factual error: Parker is looking for the phone her mom hid. She is moving a box of cereals. The cereal ingredient label has a few joke entries you may Miss at first (goat hair, bitter almond paste, false eyelashes), but the nutrition facts tab is also incoherent in a way too subtle to be a deliberate joke; sub-categories of each macronutrients exceed the total. For instance, it has 5 g of Fat in total, but 25 g of Cholesterol and 56 g of Saturated fat (at most it could be mg). (01:00:25)
Factual error: Chucky murders his first (human) victim as he was taking down the Christmas lights, making him fall in the watermelon patch in front of his house. Shane must have an uncanny green thumb, to be able to have fully grown watermelons in winter.
Factual error: Speed radar guns work by measuring the speed of an object that is either approaching or moving away from it. So when it shows Sonic running across, the beam giving the measurement wouldn't work, and he would have barely even registered on the device. (00:04:44)
Suggested correction: Subtract 27 from 2019 and you get 1992. They were 12-13 in 92 so it is plausible that those games could have been in the arcade while they were still kids.
It's set in 1989, not 1992.
The "present day" scenes in this film actually take place in 2016, 27 years after the first film is set which would be 1989. The mistake is valid.
BaconIsMyBFF
Some of the flashbacks seem to be set after the first movie.
That flashback definitely was not supposed to be after the first movie, it featured Henry Bowers.
BaconIsMyBFF
And Pennywise would have been asleep in 1992~1993 so that whole scene after the arcade makes no sense.