(Before I continue I'll let you know that I was consuming alcohol while watching the movie so my recollection may not be as sharp as I hope. Without further ado. . . )
Simply put, I did enjoy this film. It was shot very well (in both interviews with people and landscapes), the soundtrack and sound design was impeccable and set the mood perfectly (in juxtaposition with the subject matter). The narrative was carried by two rather oddly charismatic characters, Fenriz and Varg Vikernes, who are extremely important figures within the black metal scene as "founders," so to speak, of the genre and culture. Another attribute of the film that attracted my respect was the fact that a very little amount of video and other types of documentation of black metal at the time probably exists, and with the lack-thereof, seems difficult to develop a well rounded story as say, a documentary on Prince. The film also had a number of comedic moments dispersed throughout that had the entire theatre laughing (except the really black metal people in the crowd), and revealing some of the absurdities of black metal (I mean, who-- besides highly delusional individuals-- takes this thing seriously?).
With that said, if I didn't already have some grasp on the backstories presented in the movie or with black metal in general, I probably would have been lost at moments. The film did not elucidate or even exhibit a cursory "history" of the scene, but expected the audience to cull a narrative out of the haphazard personal stories. It seemed as if the filmmakers did not wish to reveal too much at first about some of the people involved and their histories and interconnections, with fear that it would ruin the climactic effect by presenting it too early on in the film. Consequently, the beginning of the film trudged but started gaining momentum about 20-30 minutes through when they began establishing some plot with the suicides, murders, and church burnings. By employing this method, the movie sacrificed clarity of some subjects early on and potentially alienated audience members unfamiliar with the scene.
The highest point of interest was with Vikernes story and how he wound-up in prison (which, by the way, Norwegian maximum security prison looks like a college dorm room, equipped with computer and all. So if you're ever interested in going to jail for a while I suggest breaking the law in Norway). Vikernes recounted the incident of murdering another famous black metal demigod, Euronymous. As he recalled the event, Vikernes, like paranoids do, felt that Euronymous was attempting to kill him first for various reasons (even though Euronymous awoke in the middle of the night to let him in the house, unarmed). He wasn't too certain when Euronymous was planning on killing him, just that he heard he was. The more and more he talked, the more and more you listened in disbelief that this guy is actually claiming self-defense. I'm not doubting that Vikernes believed that Euronymous was going to kill him, eventually, but that didn't seem like the reality of the case based on his testimony in the film. Like I mentioned above, Vikernes seems like a highly delusional individual mixed with a lot of paranoia. Furthermore, the filmmakers never seemed to reference that Vikernes is a Neo-Nazi; they only used his vaguely anti-commercialism and anti-Christianity rants to explain some of his ideology.
The conclusion I drew from the experience is an important one: no matter how utterly ridiculous something may seem (i.e. black metal), never doubt that people will do everything in their power to play dress-up and act out the infantile ideas while sometimes committing horrendous crimes.
PS: Harmony Korine's cameo is awesome.