Other mistake: Recreated newsreel of a trip to Japan by Moe Berg before Pearl Harbor attack shows copyright date of MCMXLIV (1944) in the lower left corner, 3 years after the attack. (00:16:25)
Other mistake: Just after signing the contract, you briefly see Stan in his hotel room. The smoke from his cigarette is moving downwards.
Other mistake: When Tony and Dr. Shirley are driving in a snow storm, in the view from the front of the car, the wipers seem to pass behind the snow on the windshield, and the blades appear longer than the area cleared. It's almost as if the snow was added on later in post-production. It's most noticeable if you look at the tips of the wipers as they approach the tip of the snow on the windshield. (01:51:35)
Other mistake: During the murder in the stairwell, an old woman opens her apartment door outward, and Varg kicks it shut. Apartment doors always open inward, as did Euronymous' apartment in the same building.
Suggested correction: Euronymous' apartment door opens outward into the hallway, at least in the final scene it does when he's trying to get away from Varg.