Finally finished off this excellent horror game but the ending was half interesting, half stupid.
Spoilers below in white:
First up, I really enjoyed the way they subverted the light-dark mechanic in a brightly lit lab which still required the night-vision mode to fully define the Walrider nanoswarm (while obscuring everything else).
At the end, things go full sci-fi, at least I think they do, and this leads to some good and bad points.
Good: The knowledge that the swarm would only take to derganaged/traumatised individuals which is perfect given the priest spent a good chunk of the game leading you into terrifying encounters before eventually immolating himself in front of you. At first I assumed he was mad but when Miles becomes the new host it's obvious he had a good idea all along of what his new "god" required to survive.
Bad: The infamous "exposition dump" in which we have to sit in a locked room and listen to an old Nazi scientist stereo-type explain everything is nanomachines and, contrasting with early documents, he suggests he lied to the Nazi's regarding the paranormal aspect of the project. Keeping something mysterious or unknowable is a huge boost to anything horrifying and it's unfortunate they felt the need to go this route.
On the upside, I guess they never truly remove the possibility the swarm is sentient given that it chooses to enter Miles even as Billy is dying.
Hopefully the new DLC will do a good job of expanding on the story both before and after the base game.