This game reminds me, or imparts a feel, very much of sword and sorcery, particularly in the vein of Conan, where the gods there were not particularly shiny and lovely and magic was the tool of dark forces. Anyone else agree?

Same here. Well, part of it is obvious -- Khorne's a heavy duty reference to Crom, whose most well known follower was always fighting with wizards, and Crom is most likely named after the RL pagan god, Crom Cruach, whose name means either "bloody pile of skulls" or "bloody pile of corn." Hence, Khorne.

Plus a lot of incidental stuff sounds 40kish: "Purging is at last at hand. Day of Doom is here. All that is evil, all their allies; your parents, your leaders, those who would call themselves your judges; those who have lied and corrupted the Earth, they shall all be cleansed."

From the more general perspective, just as the imperium uses romans for a lot of inspiration, chaos seems to often use barbarians (particularly the gauls) as inspiration (particularly, the Screaming Vortex seems to be supposed to be a zone of 'pagan wild space'), and the general idea of playing a roving band of outlaws in search of glory certainly feels very S&S in general.

Isn't there already a corrupted version of Conan out there? Kain, or something? Never read the novels, but recall someone explaining the character to me that way before.