Continuity mistake: When Marcus sees his baby grandson, a nurse in the background is picking up a white diaper. In the close-up the diaper is now blue.
Other mistake: The rectangular area of skin cut from the dead deer's rear side was not wide enough (or at the correct angle) to encompass the killer's entire bloody hand print; it would have missed the "pinky" finger (and possibly the tips of the second, third, and fourth fingers). Because the fingers were spread out, a shape more like an inverted isosceles trapezoid (or a much wider rectangle) would have been necessary. (00:42:52 - 00:44:09)
Factual error: Apex, played by Robert Maillet (a retired professional wrestler 6'11" and 350 pounds), forcefully slams Becky (played by 5' tall fifteen-year-old Lulu Wilson who probably weighs under 100 pounds) horizontally with her back hitting the ground from waist-high yet Becky is able to get up with no incapacitating injury that would be expected. Becky also manages to brutally kill him (as well as the three other neo-Nazis).
Character mistake: Bart is sitting on a bench outside the hotel. After Detective Espada talks to the Mercer hotel manager/owner, he goes to talk to Bart. Bart has blood on both hands and lower left sleeve. Detective Espada is supposed to be investigating a fresh murder case that puts Bart at the scene, but he does not confiscate Bart's bloody clothes, conduct a gun powder test on Bart's hands to check for residue, or take him to the police station for formal questioning. Espada did not follow police protocol. (00:17:36)
Continuity mistake: When the Homeland Security guy is sitting in the lobby in Vancouver, Canada, a girl and another man are walking behind him and across the lobby in the wide shot. But when it zooms in on him, the same people and more are walking behind him again as if they never were crossing the lobby. (00:28:45)
Continuity mistake: Bernice's bangs go back and forth between having a small section separated from the rest to not separated. Before she kisses Thomas, her bangs are separated, but combed together when they are done kissing. (00:21:56)
Continuity mistake: The sizes, locations, and smoothness of the pieces of glass remaining in the wall mirror after Aidan smashes it with a bat change. Initially, there were a few large and several smaller jagged-edged pieces around the top and upper-half of the right side. Later, there were four relatively large smooth-edged pieces spaced around the upper half of the mirror - one in each upper corner and one on each side at the middle. (00:15:48 - 00:19:33)
Continuity mistake: Brahms was quite clean for having been buried under dirt and leaves. No dirt fell off Brahms' body when Jude pulled him out of his "grave" and there did not appear to be dirt in his hair. When Sean (Jude's father) held up Brahms, the doll looked relatively clean - or cleaner compared to when Liza (Jude's mother) started to wash him. (00:14:10 - 00:15:45)
Revealing mistake: Near the beginning of the movie, there does not appear to be a curtain (or window) on the left side of the screen (e.g, when Samantha is sitting on the couch), but there is near the end when Chloe enters the now-empty room. The use of a green screen seemed apparent throughout the movie. (00:04:19 - 01:23:04)
Other mistake: Fran is unconscious near a gas stove as Marla comes to save her. As Marla is trying to move her, Fran moves her leg even though she is supposed to be unconscious.
Audio problem: When we are first introduced to Hayden lecturing the classroom, the shots from behind do not match the sound with the movement of his jaw.
Revealing mistake: After the kids take their seats at the game, the people behind them change, indicating the use of a green screen. (00:13:00)
Continuity mistake: At the "Wave Hair Salon", Ms. Gordon has a curler/roller at the top of her forehead. In some shots, it is straight, but in other shots it is angled. A little later, Christine goes over to Ms. Gordon and starts rolling down the curler to the top of her forehead as if for the first time. (00:08:04 - 00:08:47)
Factual error: During one scene, a police siren can be heard in the background. However, this was 1960/1 and police sirens were not introduced into the UK until 1963. Before that, police cars had bells.
Continuity mistake: Kelly was wearing a white thermal top over a white sleeveless undershirt. After he was thrown into the garbage can, his white thermal top was wet against his back, so he was no longer wearing the undershirt. (00:03:54 - 00:05:43)
Continuity mistake: The grilled cheese sandwich was charred while it was still cooking, but not when Jason's dad served it to him. (00:02:00)
Other mistake: The scraping sound is not coming from the man "scraping" his windshield. The snow is easily brushed off and there is no icy coating below the "fluffy" snow to realistically produce the sound of scraping ice off a windshield. (00:00:35)
Continuity mistake: Theo lays Susanna's phone down - when it cuts back to her phone is lying in the opposite direction.
Continuity mistake: James lit the cigarette he gave Amanda, and she was shown taking one puff. Amanda tells part of the Empty Man story and the ashes on the tip of her cigarette are the same when she takes a second puff. After continuing the story for about two minutes, the length of the ashes still have not increased when Amanda is about to take the third puff. (00:37:21 - 00:39:53)
Factual error: After Maya Peters is brought into the recompression chamber because of an injury, the timer is shown counting down by hundredths of a second and skips from 1 to 0 without showing 0.99-0.01. (01:24:30)