Well! I must say, this was a treat to play through. It was nice to walk around the environments, and I got a thorough creepy feeling of loneliness as I played. The sound bites were definitely of assistance there, and the fourth map, City 17 Underground was probably my favorite of the bunch from the exploration of abandoned buildings and light platforming.
That being said, I'm unsure what feedback to give as this is intended as a recreation of an unfinished product, so I will hold off on comments of nodrawn textures and the like.
One thing I must say was confusing was doors- I was never quite sure which doors were actually usable, and this lead to wallhumping and an uncertainty as to whether I had truly "completed" a map due to the lack of a level end. I am not quite sure how to make these doors more distinct other than specific use of textures to codify them, or maybe desaturating those that are unusable. Additionally, the front door on the left of the "Manhack Arcade" appears to not function.
Good job, though. Liking the atmospherics!