IMO give Fas further listens, until you can deconstruct the most chaotic parts of the album. That's why I love Fas so much. I love the complexity and Chaos. And the new song from the split, Chaining The Katechon, I beleive they've reached a perfect ballance of chaos, riffage, ambience and yeah, it's just perfect. =P But from there, work backwards, and as others have said, make sure you check out the other recent splits Mass Grave Aesthetics (From The Dirt to the Entrails), and Diabolus Absconditus [Crushing the Holy Trinity (father) Compilation] because 20 minute songs are tasty.
Then there's SMRC.
All their pre SMRC releases are darkthrone worship, and only for the most devout fans, and I'm one of them. Their 2008 compilation, Manifestations 2002, is a nice middle ground between SMRC and their pre SMRC stuff. But SMRC was a huge jump in music style.
But I love this band, and love everything they've ever released.