Character mistake: Mia's Sea-Monkey, in a vertical position, was shown sinking to the bottom the jar. It isn't clear if the Sea-Monkey was dead or if Mia was referring to it when she said, "She's gonna freeze to death, Aiden", but Mia should have known how to properly care for her Sea-Monkey (or refer to the instructions) and, realizing the room was too cold, should have done something - such as wrapped a towel/blanket around the jar and/or moved the jar to a warmer location (e.g, near the fireplace). (01:22:33)
Character mistake: Henderson asks the guy as he's leaving the room to get him some bourbon. They already drank in the bar and spat it out when they found out that everything had turned to blood, so it would still be blood.
Character mistake: Tyler said, "Charlie says you're [Ben] gonna tell your folks that you got that girl pregnant this weekend." "This weekend" is a misplaced modifier. Ben didn't get the girl pregnant this weekend; Ben is supposed to tell his folks this weekend that he got a girl pregnant. (00:22:15)
Character mistake: John shot at the "werewolf" but wasn't successful in hitting it. Instead of pursuing the werewolf, who he supposedly was determined to catch, he let it run away. Alcoholic or not, a sheriff's deputy should have done everything possible to try to capture the creature that was terrorizing the small town. By not even attempting to follow the werewolf, John missed the one opportunity he - or anyone else - had thus far to potentially put an end to the senseless and tragic murders of young ladies. (00:55:35)
Suggested correction: Dude's daughter was attacked and bleeding from the head, of course he didn't pursue it.
Suggested correction: He didn't go after the wolf because his daughter was hurt, and his (albeit misguided) parental instincts took over. It's not at all a character mistake for him to prioritize making sure his daughter is all right over chasing a perp. Most parents would probably do the same thing.
Character mistake: In the beginning scene, the doctor cuts his finger open while performing the operation. However, despite the high risk for infection, especially given the extraordinary circumstances of the procedure, and despite the fact he's a medical professional... he doesn't immediately run to rinse off his wound and change gloves. And you can't argue it's Tomie's supernatural influence, because they haven't even seen her yet.
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)
Character mistake: The news article on the murdered gentleman David Carradine discusses has the word existence spelled wrongly. It says existance. (00:37:57)
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: 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: The ref says there's no rules before McClure fights Whiplash but she tries stopping them later.
Character mistake: The American flag at the New Orleans Mardi Gras is hung the wrong way on the building.
Character mistake: In the very first scene, in the first shot you see a sign in Spanish that says "NO PASE por orden del departamento de arquiologia". The correct Spanish word is arqueologia.
Character mistake: When the second fog bank rolls in, the weatherman says it is coming from the south-east, and the DJ says the same thing once; the second time, however, she says the south-west.
Character mistake: Set in Texas, the Sheriff threatens the wrongdoer with the gas chamber. Executions in Texas at that time were all by electrocution, namely by "Old Sparky," the electric chair. Texas has never used the gas chamber for executions.
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: Leland Palmer handles Laura's body without any gloves when wrapping her and disposing of the body. As with any respectable FBI investigation, upon finding her body and checking for fingerprints, they should've connected Leland to Laura's death within days. (02:05:00)
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: Jill states that a 5 kiloton nuclear weapon will sanitise the city, however, such a yield is far too small to destroy the city. (00:42:00)
Character mistake: John would have no reason to ask the CT technician if she had any results. He says "that was a long one," indicating he's had this done before and should know it typically takes around 24-48 hours to get results. (Likely just a line of dialogue added for the benefit of the audience, who may not know.)
Character mistake: When Chafuka is controlling the zombie Barry with her voodoo doll, he's supposed to be repeating her words so precisely that he even imitates her accent. But when she says "that darn fool paper, it fall on the ground," Barry repeats it as "The darn fool paper fell down to the ground."