I enjoyed this and I would be just fine with some more multi-parters, as long as they're like this and they include some uncanniness fairly early on, or at least in the first part, so that it's not part 1 Normal, part 2 Uneasy, part 3 AGH! This was weaving and building the dread throughout in a way that I appreciated.
I also enjoyed the unexpected elements, like the protagonist's relationships with his lover and the lover's old friends, and the matter-of-fact creepiness of the personality at the end...
But if I'd been through that, I wouldn't be moving to somewhere even as near to suburban as Kingston is (bears maybe, cougars hardly!). I'd make my life in a high-rise nowhere near nature. Although I guess i'd still have to worry about ... altered ... humans then.