Science-fiction in my book is "science by fiction", i.e. scientific theories explored/discussed through a fictional setting. That's why Star Wars will always be 100% fantasy, no matter how much esoteric technobabble they tried to cram in as the franchise started to grow, that's why Star Trek is scifi even at its silliest (and the technobabble is actually entirely irrelevant to its SF status), and that's why something like the Strugatsky brothers' Hard to be a God is rock-hard scifi even though the main gist of the story is set in an exaggerated medieval feudal state.
The way I see it, what makes Chaos ultimately qualify as scifi is Allen Stroud's alt-history dabblings. On its own it would just be another fantasy setting.
But the problem is, indeed, it zlots at Vlurxtrznbnaxl.