What I like about metal and about this album in particular is that it appeals both to our taste for musical complexity and to our laziness of actually listening to anything outside of the rock aesthetics (classical, jazz, other types of popular instrumental music etc.). So yeah, it is nicely varied, which means you can sit down and listen to it and possibly not get bored. For the occasional person who actually might get bored, goes the classification “dark ambient”, which is clearly a trick to push instrumental music to people who don’t actually have the attention span to listen to it.
For the rare occasion that someone might actually pay attention, this isn’t as metal as it would first seem to be. Some riffs every now and then sound more like arena rock riffs searching for a chorus, and then they are gone just like that, giving place to a more black metal sounding riff, which then sees the drums, which were sporadic, suddenly come out to the front, then suddenly drop, then the riff changes again and there it goes for a half an hour or so that must have been hell to record.
This is actually the only problem I see with this. Instrumental music needs structure or else it just kind of wanders around, looking like collages of musical ideas which might not have anything to do with each other. Unfortunately this is what happens here. There isn’t even a primitive structure of introduction, build up, going crazy, sudden break from craziness, slow build down, closing remarks. The tracks go up and down then up and down again and as far as I could notice, most riffs never come back at all. Not repeating musical ideas is a good thing, earning this music the “progressive” title, but the lack of structure sadly also makes it “ambient”, since there isn’t really much reason to pay attention to the whole thing. You can wander off then come back guilt free.
Live, of course, would be another story. Stoned people could go crazy to the sound of this and only come back a week later. Maybe that’s what it was supposed to do. Maybe the stoned people are the musicians themselves. But then it doesn’t have much originality. It’s really just a massive collection of riffs, some well polished and dramatic, others more hurried, with matching drumming, and when it’s over it leaves you there with the impression that it could go on for hours more and you still wouldn’t pick up anything else than you have just picked up, which is really nothing but the familiar feeling that metal is awesome.
tl;dr: It’s metal wankery. Enjoy.