✓ Fits the first-person shooters cluster, with shooter, first-person shooting and single-player focus
≠ Stands apart with survival mechanics, horror tension and dark, oppressive atmosphere, while skipping adventure storytelling
The AI Director is the whole design: it places hordes and items based on how well you are doing, so no two runs of a campaign play the same and tension stays authored without being scripted. Four campaigns only, which is thin, and the sequel superseded it so completely that finding populated servers now takes patience.
It predates Abyssus by 17 years, with what that implies technically.