Slides from 5 stars to 4 as it goes (endings are hard), but the truth is, I was pretty much in love with this for the duration. And by "in love" I mean fret-racked, clammy with trembling, worrying wonder, and cringing in cold space with the cowardly moon. This is really good, scary TV. Like most of the best horror, it's grounded in psychic damage, and shot through with rather than merely ornamented by strangeness.
Great premise, well directed and amazing practical effects. The creature made of teeth really freaks me out, it's pretty disturbing. Besides that, the acting is also pretty good, it brings some weird elements in what concerns behaviour, reminds me of Twin Peaks a little bit.