Plot hole: Spoilers. It's revealed that the barn game takes place at an old farmhouse owned by the family of Jill Tuck - Jigsaw's widow. It's public knowledge that she was married to Jigsaw and that buildings they owned served as the headquarters of several past traps, so the barn should have been investigated at some point in the meantime. Ten years have passed. It makes no sense that the barn was never investigated and that the bodies of the barn victims were never discovered.
Factual error: During the opening scene in 1988, a silver TV from the late 90's/early 00's is in the living room/dining room area. (00:02:10)
Other mistake: When they hit the deer, the passenger side mirror and lower quarter panel was damaged, when the deer not only came from the other direction, but also seemed to be in the air when it got hit.
Plot hole: It seems highly unlikely that Lucas would be able to "mess with" Mr. Butler's application for a professorship position, or be able to accomplish what he did in such a short amount time. Off-screen, Lucas went into Mr. Butler's briefcase (foolishly left on his desk in the classroom during lunchtime) and (correctly) assumed Mr. Butler's application was on his laptop. Lucas would have to be able to figure out Mr. Butler's password (something that could take forever), find the right file on his laptop, read or scan the application to determine what he could do to mess it up, write a new answer for "qualities that make me a good teacher", and leave the classroom before anyone saw him. Lucas would also have to assume that Mr. Butler would not notice the change when he printed the application, made a photocopy, and double-checked the application before inserting it in the envelope and mailing it.
Plot hole: Buddy is seen at the end of the movie going on the bus that will be featured in Jeepers Creepers 2. When the students and staff encounter the Creeper why didn't he inform anyone that he had encountered the Creeper earlier? The only person that seemed to know anything was one of the girls having a premonition.
Continuity mistake: On the third and fourth day, Carter's roommate shows up earlier than the first 2 days. And Tree's suspect tips notebook every day don't reset and the line and erases are the same.
Other mistake: To stop herself from bleeding after removing the tree branch from her body, Jen heats the wrapper of a beer can and places it against the wound. Later it is revealed that doing this resulted in the logo being branded onto her skin. However, if the wrapper was placed on her skin and the logo was facing towards her, then the logo should have been mirrored, but it's not. (00:57:40 - 01:05:20)
Revealing mistake: The bartender (Kateryna Korchynska) offers Ethan two lattes on the house. She hands them to him, and he walks out. No opacity from the liquid can be seen inside the plastic cups, and when he is moving away from the counter he leans forward quite a bit, showing the inside of the cups, squeaky clean. (00:08:00)
Factual error: When the bank robbers pull the money out of the vault, they claim all the cash is from 1982. Yet most of the bills have large faces, which was introduced into rotation in 1996.
Plot hole: There's no way that plane could have crashed and stayed intact like it did.
Other mistake: When Harry Hole gets a call but isn't there to answer, Katrine Bratt picks up the phone and takes a message. Rebecca from Telenor Security tell her they picked up a cellphone signal from a missing person. She tells her the coordinates as Parkway 1, 0139 Oslo. On Katrine Bratt's computer you see the coordinates as Parkway 1, 0350 Oslo. (01:13:15)
Continuity mistake: When Nicholas Cage and his kid are enjoying a flashback, the ice lolly keeps shrinking and growing throughout the conversation. (01:14:00 - 01:15:00)