When Euronymous is introducing Manheim as the drummer in the rehearsal space, Manheim is sitting behind a 5 piece, single bass, blue drum kit. When they being playing, he's sitting behind a 9 piece, double bass, blue and white drum kit.
When Dead commits suicide with the shotgun, the sound of an empty shell is heard bouncing around on the ground. He is using a break-open shotgun, which doesn't automatically eject spent shells.
Euronymous send Varg a letter and contract, the date on top of the letter say: 2/3/93. In Norway, March 3rd. Varg is then seen signing the contract and take off to commit the murder. Euronymous was killed on August 10th. There is no answer given to why he waited 5 months to sign.
Lords Of Chaos depicts Euronymous murdering a gay man who makes sexual advances at him in a park. Notwithstanding the doubt about the details the murderer gave in his story, the person who killed the gay man was Bård Guldvik "Faust" Eithun.
One scene shows Øystein Aarseth standing in front of his record store, Helvete, but there are signs in the windows that read "Neseblod". (Neseblod is a record store that moved into the location of the real Helvete in 2013, twenty years after the film takes place and in context of the movie not meant to be Helvete, but just another record store in Oslo.)
In the end credits, Pelle 'Dead' Ohlin's name is misspelled as 'Pelle Olhin'.
When Varg leaves the video store on 10 August 1993 with a copy of Die Hard 2 (1990), the video cases for several films that would not be released until several years later can be seen in the window, including The Bone Collector (1999) and Analyze That (2002).
After the scene where Øystein Aarseth cut his hair he plays the LP containing the Soundtrack of The park Is Mine by Tangerine Dream. This soundtrack wasn't released until 1991, and never released on vinyl until 2020.
The story takes place in Norway but all characters speak English instead of Norwegian (or Swedish, which was Dead's native language).