Continuity mistake: When Butch is talking to Dawn in his room, he puts on his headphones and begins talking to some unknown being and seems to be in a trance. His head is resting flat on his pillow as he grabs Dawn's arm. Just after she pulls away, Butch's hand is in the position as if he was still holding her. However his head is now resting up on the headboard. He couldn't have propped himself up with his hand in that position, especially in the matter of a few seconds. (00:40:40)
Continuity mistake: In the car at the start, when Hamilton says it's like the fourth blackout today, Michael corrects her and says it's the fifth. When he says this, he is leaning forwards some as he looks up out the windshield with his mouth partly open. It cuts to a different angle and suddenly he's leaned back in his seat fully and his mouth closed. (00:01:30)
Continuity mistake: In the basement when the girls are talking, one mentions to Chloe that she and Carl would make an adorable couple. Chloe's left arm is stretched up above her head in this shot. But in the next shot when she corrects her on the guy's name, it's suddenly down by her lap. (00:06:10)
Other mistake: During the murder in the stairwell, an old woman opens her apartment door outward, and Varg kicks it shut. Apartment doors always open inward, as did Euronymous' apartment in the same building.
Suggested correction: Euronymous' apartment door opens outward into the hallway, at least in the final scene it does when he's trying to get away from Varg.
Continuity mistake: After Asher is separated from Quinn he's looking around a room with a flashlight and finds the killer. We can see the killer's eyes but a few shots later there is mesh over the eye holes of the mask. (00:52:15)
Character mistake: When recruiting Burt to help repel the Graboid attack in the arctic, one of the team members says he's ideal for the job because of his experience hunting them on two continents, a reference to the first two films (Nevada and Mexico in North America) and Tremors 5 (Africa). However, this repeats the mistake in Tremors 5 in overlooking the Argentina incursion stopped by Burt at the beginning of Tremors 3, which gives him experience fighting Graboids/Shriekers/Ass-Blasters on three continents, not two. Burt, himself having overlooked Argentina in Tremors 5, does not correct her. And it's not as if the film is completely ignoring Tremors 3, since it shows the flashback of Burt being swallowed by a Graboid in that movie, which is how he got infected with the deadly parasite killing him here.
Factual error: The police officer that shows up does two stupid things in a row that real police would never do. When investigating a kidnapping, he calls in what the car was they were looking for. Which he sees. Instead of calling for back up, or even mentioning to dispatch that he found a car that looks like it, after coming from a murder scene at a gas station and following a map left behind to this spot, he approaches the car alone, without calling for back up, or drawing his weapon. Shortly thereafter, he finds the kidnapped boy inside the car, who tells him the man who took him is in the house. The officer then proceeds to go into the house alone to look for a dangerous kidnapper without waiting for backup, even mentioning to the kid that his partner is on the way. (00:32:00 - 00:33:35)
Continuity mistake: When Jason lunges at Batman with his knife, there is a pile of garbage by the wall where he lands. In the first shot the barrel by the garbage is wooden. But in the next shot it's suddenly a metal barrel/drum. It then changes back to a wooden barrel again. (00:04:20)
Continuity mistake: After a camera shift while talking to Mr. C, Chris' jersey was pulled down more over his pants (lap), but his hands were pre-occupied playing with the string on his hooded sweatshirt. (00:06:35 - 00:06:58)
Factual error: Spoiler! The cultists burned Mandy alive by wrapping a sleeping bag around her, putting gas on her and hanging her from a metal swing set and setting her on fire. After Red frees himself later and craws up to her remains, it's shown that she is barely a pile of ash with her skull still somewhat in shape when he picks it up. It then crumbles into just ash showing she had been fully burnt to the very center. This would not have been the case with how they burned her. Their was nowhere near enough heat or kindling to keep her body burning long enough to turn completely to ash with no remains like that. She would have died, yes, but would have mostly stayed intact as a single body burnt very bad. Bones, features, charred organs would still have been left behind. (01:04:00)
Revealing mistake: At the beginning of the movie, the protagonists dump the corpse of an agent in the middle of nowhere. The guy is stone cold dead...but you can see the carotid pulse on the right side of his neck, under the fake blood. (00:03:10)
Revealing mistake: Davey at the beginning of the movie is looking at the newspaper he's delivering to Mr. Wayne Mackey. Just from a glance at the page you can tell that something is off, since the article supposedly about a missing boy appears to be written entirely in first person. Upon closer inspection, turns out that it's filler text from chapter IV of Robert Louis Stevenson' s "Treasure Island". (00:01:30)
Continuity mistake: When Mrs. Marsh is setting Jonathan's plate in front of him, the mashed potatoes are to Jonathan's right, but when the plate is set on the table, a close-up shows the mashed potatoes are to Jonathan's left. Afterwards, the mashed potatoes are to Jonathan's right again. (00:35:55)