Listened four times now. It's like stepping into a parallel dimension, or several, and I think that's one thing they try to do with their music. There's an interview somewhere where Mike or Marcus is talking about trying to imagine if the standard genres we know developed different ways, branching into things that don't really exist for us. Or like pop songs from a parallel 1970's.
I'm thankful that the vaults of modern culture (say 60's on) have such breadth that there can still be 2 hours of music like this, which would totally stupefy identification by any one individual without the aid of Shazam or the like, or even a community of many thousands with whatever technology at their disposal. They probably knew that they would be lifting many of these things out of obscurity, relatively speaking.
It's not ALL that different from what some vaporwave artists and curators do. And that's not meant as a slight at all. There are some mixes on youtube I've listened to so many times and had such appreciation for -- that they are masterpieces in my mind, outside and above any particular artists or songs the mix features. This is how I think the Societas mix will age for me, and I quite love it already.
One correction I noticed for the tracklist Joyrex posted is the Flayer song is linked to the wrong mix. Should be this one. Just noticed because this was the first song I wanted an ID on. Such a groove.