
Character mistake: Ginny should've been loaded head first into the ambulance, not feet first.

Character mistake: When Erickson is telling Strahm that he no longer has any jurisdiction over the Jigsaw case, he mentions that over a dozen dead bodies were recovered at the meat packing plant, including two cops. There were in fact only 10 dead bodies: Danica Scott, Judge Halden, Timothy Young, Jeff Denlon, Lynn Denlon, Jigsaw, Amanda, Art Blank, Officer Rigg, and Detective Matthews. (00:20:28)

Character mistake: There's no way that using a regular needle and thread to sew up that wound would work the way it's shown. Anybody who knew what they were doing - which John Cusack is portrayed as knowing - would also know that using unsterilized materials and instruments without a sterile field from an uncleaned massive open wound is a great way to kill your patient.
Suggested correction: The main plot of this film takes place inside the head of a murderer with dissociative identity disorder. The fact that stitching up a wound in that matter wouldn't work is irrelevant to the fact that it is how Malcolm is playing out the scenario in his head.
You're making a good point to invalidate a "character mistake", but couldn't the entry be reclassified as a "factual mistake" and stand as written?

Character mistake: When Marisa leaves the diner, you can see the door has a "Push" tag. However, the door opens inwards, and in fact to go outside she has to pull. (01:08:00)

Character mistake: Sally and Franklin's last name is Hardesty, but for some reason Franklin refers to their old home as the "Franklin place."

Character mistake: Doreen/Mom told Rose she'd be back from the store "in a jiffy." Rose asked, "How long is a 'jiffy'?" and Doreen replied "in about an hour." "Jiffy" typically means VERY fast (perhaps as short as a nanosecond) and, even if people have different perceptions of how much time a "jiffy" is, an hour is excessive by general standards and does not reflect its true meaning. (00:32:50)

Character mistake: The Captain of the USS Fragasso comes onto the bridge. A Petty Officer says, "Officer on deck," and salutes while looking out the forward windscreen. He should have said, "Captain on the bridge" and not saluted.

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.

Character mistake: It doesn't occur to our heroes (admittedly kids) that you don't need to understand German at all in order to read it out loud. It's arguably easier to read than English! The only inscrutable letter would be "ẞ" but Scary German Guy's right there for help. (True, this is essentially what they end up doing in the end, but they still come about it through a "you don't need to be of age to be a virgin" realization rather than the even simpler "you don't need to know German.").

Character mistake: When Joan is searching the web looking for information on what monkeys eat, there is a section on the screen that reads "The diet of monkeys varies form fruits, leaves." Obviously the correct word for this sentence should be "from" not "form." (00:36:21)

Character mistake: At the hospital, the inspector manages to get from the nurse the file of the patient with the liver condition. Forgetting the fact that the Turin, Italy hospital is using English for its documents (it's simply a cinematic convention), the problem is that the letterhead of this document says "Department of Chronic Deseases", misspelling the word.

Character mistake: The little girl asks Kristen "what's your name?" Kristen replies "Kirsten". (00:05:59)
Suggested correction: I hear her say "Kristen." The transcript and subtitle even say "Kristen."

Character mistake: The American flag at the New Orleans Mardi Gras is hung the wrong way on the building.

Character mistake: In the highlighted newspaper article entitled 'DeFeo Son Accused' about the killings, the first sentence of the article ends with two periods. Also, in the 3rd sentence, the word 'psychiatric' is spelled "psuchiatric" with a 'u' instead of a 'y'. (00:01:05)

Character mistake: In the scene discussing the provenance of the mirror, the girl stated that Sherman marched to the sea in 1865. It was actually 1864.

Character mistake: There's a note from "mother" on the wheel at the diner. Right beside it is an order with the wrong total. 2 hamburgers for $1.95 each. 2 fries for 90 cents and 2 drinks for 90 cents for a total of $5.70. The waitress put $3.70 for the total.

Character mistake: The Sheriff calls for Drayton Sawyer to bring out his son Jed (Leather Face) in the movie's opening scene. But it's long been established that they're brothers.
Suggested correction: This is meant to be a direct sequel to the original film, and ignores the other sequels. And if memory serves correctly, the first movie never made any mention of them being brothers. (I just checked and the Texas Chainsaw fandom Wiki backs this up - the original film makes no reference to them being brothers.) So therefore, it is not a mistake if this movie re-writes him as being Leatherface's father.

Character mistake: When the sheriff confronts Charlotte after she has shot at the bulldozer operator, he tells her that her gun is unlicensed, but he will overlook it. Louisiana does not have, and never has had, any form of gun licensing or registration.

Character mistake: During communication with ATC the co-pilot states their call sign followed by the read-back of ATC instructions. This order is incorrect. In reality a pilot or co-pilot reads back the instructions from ATC and then their call sign or tail number prior to ending their transmission.

Character mistake: Marjorie's supervisor said the police found Nathan "torturing an animal [dog], there was a struggle and he assaulted one of them." Marjorie then asked, "Is he violent?" Her supervisor replied, "I have no reason to believe so. I mean, he did resist arrest, but that's probably out of fear" and the mental health team said there was "no obvious psychopathy." Social workers/mental health teams should have assessed cruelty to animals and resisting arrest as indicators of potential for violence. (00:03:55 - 00:04:30)