When Jonas is hit by the car during the bus chase scene, in the close-up shots of the windshield he clearly cracks it but in the wide shots it is unmarked.
When Jonas is riding in the car during the bus chase scene, the blood dripping down his head is in different position than when he looks in the mirror to wipe it away.
When Jonas takes Frøya to the dump to see where Tanja was found, the site is so very tidy. No flies, the bones are not oxidized nor discolored, and everything looks staged. Dumps usually have a nasty smell and the actors do not seem to notice much of an odor.
It is impossible for the human body to stay awake for a week. Jonas would've likely collapsed after three days of not sleeping.
Hagen shows Engström a spent cartridge and says it is from a Norma (Swedish) gun, implicating Engström because he is Swedish, however Engström's gun is a Berretta, shown clearly on the gun case as he packs it in his bag.
Early in the film at the autopsy scene, the boom mic can be seen momentarily at the top of the screen.
Tanja's right eye twitches during the autopsy when Jonas fingers are near it.
Jonas could have asked for a different room, covered the window with foil, or slept with his head at the foot end of the bed rather than remain sleepless. Also, rather than be so hot and sweaty, Jonas could have just removed his coat.
When Arne is shot in the leg he is whimpering in pain, then when Jonas arrives he stops and looks up to Jonas as if to ask, "What is our next line?" Surely, Arne would still be in pain and not just act like nothing happened.