De Mysteriis Dom Sathanas is one of my favorite albums of all time. To me it sounds like Celtic Frost meets Immortal. DMDS has droning, ritualistic passages(Celtic Frost) interspersed with fast war-like anthems(Immortal). Mayhem definitely composes melodies better than Immortal. Immortal's songs have a sound concept, and I can see what they were going for, but I think their melodies failed to truly conjure the emotions they were meant to. Mainly DMDS differs from Pure Holocaust in that there are no "beautiful" passages and there is no cheesiness. This is a serious album while Immortal seems to have never taken themselves too seriously. This is why I view that album as unique: the album has only one goal, sticks to it, and remains interesting. I also think that a good portion of the album can be classified as ambient. Attempts at ambient black metal have mostly been failures whereas this album succeeds. Mostly the album is just very well-executed. There are no unnecessary elements. Everything was thought through and every element has a purpose and masterfully executed. There's something weird in the drumming in the album too, but I don't know what it is. Whatever it is, I love it. The only complaint I've heard of the album is the singing. I used to hate it and thought it was effects on a crappy singers voice. Then I found out that Attila was throat-singing and "understood" the singing. When you view it as throat-singing, the vocals don't sound crappy at all, just a different style. You have to understand that it's not a crappy attempt at black metal vocals; it's something completely different that happens to resemble black metal vocals. My personal criticism is that the songs could've had more well-developed songs. On the album, long passages would go by repeating the same riff and they'll just change the drumming pattern to make it sound like the song is developing, but it's still just the same riff. I guess it demonstrates that the emotion of a melody depends on the context. Since this is one of the defining albums of black metal, if they had composed more complicated melodies, perhaps later black metal acts would have sought to out do them rather than playing the same simplistic riffs like nearly all black metal bands use. I think I'll stop here. It's definitely a good album and important, though I think the impact of this album wasn't as great as that of the other classics.