This game really resonated with me on all levels, and in general I'm using this as a shorthand for what type of books I would like. I was most attracted to the atmosphere, setting and the sense of mystery, unease and the existential questions brought up by the storyline.
For context, SOMA deals with themes of transhumanism, AI and what it really means to be human using both horror and sci-fi as the vehicle (and the two main characters of the video game, as well as the setting and scenario itself.)
I guess I would call what I'm looking for "into the rabbit hole" fiction? Any horror that includes slashers, doesn't ask big questions (lacking grand stakes) or say even detective fiction is off the table.
The kind of unease that is gathered from ideas, atmosphere and a sense of "unravelling", mentally and existentially, would be appreciated. I was also a fan of I Have No Mouth, and I Must Scream, to further give data.
But to cap it off, I am looking for mystery, unease and a combination of both horror/sci-fi, though it could be either or.