Wow, what a great, interesting throughout, sci-fi adventure movie. Yes, even though it's set in one location, with basically two characters, it has everything a good old quality mid-budget film had in the 90's - multilayered story, romance, twists and reveals, even if sometimes predictable for a genre afficionado, 'edge of your seat', tense action sequences, and awe of discovery, with excellent creature/mutant design. There's one particular cool scene that brought back those Aliens feelings, and it happens Sigourney Weaver is in this too - for a very short couple of cameos, but she makes them count!
Overall I loved it, Anya Taylor-Joy is a joy, to coin a phrase.
As a cherry on top, it ends with the great Alison Mosshart singing in a featured The Dead Weather song!
P.S. Seen more than a couple of people mention Annihilation as comparison, and have to note, to those who felt like me especially, that Annihilation was a boring incoherent mess, while this is nothing like that.
One of those decent, above average action/horror/sci-fi mash ups that we wish there were more of and that they certainly don't make enough of any more.