I guess the Tchortists have a vaguely Lovecraftian-cult vibe to them, but only to a point. They're actually relatively approachable and willing to talk about Tchortism, where most cults to Lovecraft's Elder Gods are pretty insular.
Tchort itself is not much of a cosmic horror/eldritch god. Even though some parts have extraterrestrial origin (psionics, possible assimilated Godman DNA) you pretty much learn what Tchort is (whereas eldritch horrors are shrouded in mystery essentially by definition), and once you encounter the being itself, it's actually quite vulnerable (in contrast, it would be effectively impossible for a human to "defeat" an Elder God, and never in a million years would you be able to harm one with conventional weapons).
The cube is slightly closer, by merit of its unfathomability and mysterious origin, but I'd place it closer to Roadside Picnic (Strugatskys) than Lovecraft, as it's not presented, in and of itself, as something terrifying/fundamentally wrong.
