Character mistake: Given Billy still remembered and recognized him it seems strange Kate doesn't when she mistakes Daffy for Gizmo.
Suggested correction: Billy spent significantly more time bonding with Gizmo in the first movie - days and days. By contrast Kate had very little actual time with him.
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: Reina asked Cory if they could "do that thing" because it was helpful for her medical school training. Reina then put a raw slab of steak/meat across his forehead and made slits in the meat as well as jabbed at it. A medical student studying to become a brain surgeon should know about and practice the safe handling of raw meat. (00:23:10)
Character mistake: When searching the database for the missing girl, they find her and it says missing since 7 January 2021. When Caleb read it, he says "missing since February..."
Character mistake: When a helicopter winch operator tries to get the gurney with injured Jim inside the helicopter, he doesn't have any gloves on. No wonder his hand gets injured when the cable breaks loose.
Character mistake: Daphne's mother is the one who pressed her husband to tell her the truth, but she is cheering when he says about the basketball anecdote that it was 'real', when later he corrects himself saying "real-ly me, disguised as a mascot." (00:17:25)
Character mistake: Nolan said, "Everybody knows that no sharks swim in freshwater" and Spencer said, "They don't come into freshwater", but there are freshwater sharks (e.g, river sharks) and bull sharks (not true freshwater sharks) can survive in saltwater or freshwater. Jacob Harper (National Aquarium) pointed out eyewitness accounts of sharks swimming up the Mississippi River and "bull sharks have kidneys that recycle salt" but did not mention the glands near their tails that help keep salt in their bodies. (00:08:08 - 00:29:50)
Character mistake: When John meets his clone in the rundown house he lives in, the clone has a British accent and tells him his story. John has an American accent. When the real John tells him "I'm not like you, I had a wife, a family, a daughter" he mistakenly uses a British accent.
Character mistake: When Annie is in the red truck, she says that she'll be cooking for ten staff. When Alice goes to the beach, she tells Bill that everyone has arrived except for Annie. Even if she had arrived, there would only be eight of them: Christie, Annie, Ned, Brenda, Jack, Marcy, Bill, and Alice. Two shy of what she told the truck driver.
Character mistake: There are some musicians at different times in the movie. One of them is playing a moraharpa (traditional Swedish instrument, a predecessor of the nyckelharpa), but holding and playing it incorrectly. (00:38:37 - 01:39:45)
Character mistake: The Cadillac is identified by Robby as a '57 Eldorado. It's actually a '57 Series 75 Limousine.
Character mistake: Andy speaks of Billy changing in the two months after he was hired when he was hired in the spring months ago.
Character mistake: When Chucky is looking up the information about Andy on the computer, the word juvenile is misspelled "juvinile."
Character mistake: When they're making the protection circle they make a star of David and not a pentagram, 6 points in a star vs 5 points.
Suggested correction: I don't think there was anything in the movie that dictated a pentagram had to be used. In the book of protection rituals they were using, the particular ritual showed a picture of the star of David they needed to create, so that's what they used (plus salt).
To add to the correction, what the mistake refers to as "Star of David" is a hexagram and the use of hexagrams in the occult are not uncommon. You can find salt protection circles that use the hexagram.
Character mistake: In his opening prologue, Burt says the Graboids have been contained to the Northern Hemisphere, showing a map highlighting the Graboid attacks of the first film in Nevada and the second film in Mexico. However, it overlooks the Graboid/Shrieker attack in Argentina, in the Southern hemisphere, shown at the beginning of Tremors 3, an incursion Burt personally put down. It's not like it was classified - characters in that movie talk about it being reported by CNN, and characters in the Tremors TV series talk about it as well. And it's not like Tremors 3 is no longer canon, since Burt makes two references to being swallowed by the Graboid in that movie (which also becomes a plot point in Tremors 6).
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 Leon goes to see Susan Hoff with his photography portfolio she tells him he needs improvement. After she leaves, Leon tells Jurgis that he thinks she hated his work and Jurgis tells Leon "when she hates somebody's work she gives them about a minute, you got three." In reality, she actually did give him one minute almost to the second. (00:06:58)
Character mistake: The prosecuting attorney told William, "In the interests of getting this thug [Danny] off the streets as soon as possible, his attorney has agreed to plead guilty to assaulting an officer, possession with the intent to distribute, and resisting arrest, and that's all in addition to his parole violations. We're looking at five to seven [years in prison]." The parole violations alone are sufficient to get Danny off the streets immediately. (00:09:34)
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 Dr. Elkins is measuring the Killer Whale, she says "111 centimeters" followed immediately by "68" (centimeters). But her arm spread shown when she says that is not 111 centimeters - about 3.6 feet (1+ YARD wide). It's more like 2 feet. The "68 centimeters" is actually more accurate for the shot though: 26 inches, which is shown.