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.
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)
Other mistake: Where did those spikes above and below the rear door come from? They exceed the height of the door.
Other mistake: What Lucas supposedly did to one of his teachers at his previous high school (Paul Garrett at Milton High School in San Francisco) is far-fetched. Paul told Mr. Butler that Lucas also blackmailed him for an 'A' by videotaping him in his house drinking alcohol with an old friend. Lucas hunted down Paul's old friend (how would Lucas know about this friend?) and paid him to get Paul - a recovering alcoholic - to start drinking again (how would Lucas know that his teacher was an alcoholic, eight years sober?). Moreover, it doesn't make sense that someone's old friend would accept money from a teenager to get his eight-years-sober friend to drink. Lucas may be clever and conniving, but he was still a kid - someone educated adults should be able to outsmart... or at least not get duped by him.
Other mistake: Derek changed into Tyler's clothes to escape the hospital and take on Tyler's identity. However, it does not look like he remembered to put his blue hospital ID band onto Tyler's right wrist. Hospital bands are usually securely on and not easily removed (or removable without breaking them). When the nurse was removing Derek's (actually, Tyler's) wrist restraints, there was no blue hospital ID band on his right wrist. He asked, "How do I prove to you who I really am?" (No ID band!). (00:21:30 - 00:24:37)
Other mistake: This film shows that John Kramer is buried in a public cemetery, complete with an identifying headstone. Given that he was a notorious serial killer, his remains would not have been buried in a public place, as it would cause his gravesite to become a macabre tourist attraction.
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)