Unfailing.
Ever since I played the first few Submachine games, I kept thinking it was some underground facility in some remote area. Once I got to The Lighthouse, the thought of a derelict covert base hit me. The Loop impressed on me that whatever this was it was big, and again and again I kept running into new mysteries. Multiple subterranean structures, as if a whole largish town had been buried.
And now I reach the core and find evidence of a post apocalyptic scenario, in which not just Earth, but possibly the whole universe for all I can figure, was destroyed, torn apart, and strewn everywhere, and that a few people now traverse the ruins with the technology whose creation brought about the disaster.
This series never fails me.