In the case of Avichi's latest, the listener will surely notice that Aamonael (that's a hard one to spell without double-checking) has added elements to the overall sound that are foreign and off-putting. I don't think anyone really expects the presence of keyboards and clean vocals. That's what we get here. And while they are well-executed, I can't help but think that they are a distraction.
"Repercussion" is a theme played on piano that is further developed and elaborated upon in the title track. Seeing as these two songs operate as opening/closing of the record, they obviously take on a greater importance.
That's all well and good, but I don't consider piano to be a necessary element of black metal, and if I wanted to listen to piano, I'd choose something more appropriate.
The three shorter tracks are intense blasts that are played at a fairly high tempo and don't lack for energy. Not surprisingly, I enjoy these the most.
"All Gods Fall", on the other hand, is played at a languid pace. It's not a bad song, necessarily, but it's a bit directionless and lacks the intensity shown in the previous three tracks. Also, since there are no engaging rhythms (in addition to the aforementioned lack of intensity), the song really doesn't draw me in like it should. An epic-length track needs good pacing, solid rhythms, and maybe a touch of melodic content to really shine. "All Gods Fall" lacks all of these things and basically goes nowhere.
When Catharsis Absolute is really cooking, it is a strong and enjoyable listen. Unfortunately, the variety that most will likely praise turns out to be its undoing to my ears.