Its very nice work and I like how it remains in scale! This is a small single player horror game and it knows it. In an age where everyone feels the need to broadcast every stick figure he drew on all social media outlets and, of course, release it for 4,99 on steam your approach is a breath of fresh air.
The game is an oddity to me simply because I saw a lot of attempts to bypass texturing and having an art direction by vomiting a pixelate or retro shader over a project HOWEVER your project actually
works visually.
It works really well and does have that vibe you had while playing System Shock on PC or something like the Alien Trilogy on the good old PS. Just this visual style where I can make out very well what I am seeing but my mind is filling out the blanks. I could very well picture how this game would look without the postprocessing as I know all these assets and surprisingly, with the additional definition it would have this greyish unrefined look of early FPSC games, it would be apparent that the media is from different packs and the enemies would stand out HOWEVER, with the postprocessing it all works. That hallway early on with the red tinted metal is oppressive and creepy while it would have been dull and underwhelming without the retro effect.
This game is well designed for the most parts and I only have a few gripes with it in its current stage but I want to wax about retro themed projects a little more. As I mentioned earlier, you get a whole bunch of people that try to hide horrible design with it and they usually still rely on high polygon models and unoptimized environments. So their "retro" game runs and is the size of something very taxing on the hardware while it looks like its 20 years old. There is a game on steam that claims that it wants to recapture the look of the AMIGA games but its just all of the GG content with the cartoon filter on top.

This is dishearteningly bad and dishonest and I'm glad to see that you actually knew what you where doing by showing a lot of restraint with level details. It all works so well together like the game
Synther where it really looks meant that way and better in its pixelated form. Given your design choices, this is also the first FPSC game I ever played where the little LED flashlight looked good. (Just don't put a full sized flashlight in the player then can't pick up

)
The game had a nice atmosphere to it but it could use a few more ambient sound effects here and there. You can use "cutters" to break up the walls here and there or add a few doors that can not be opened. Communicate to the player that there are many corners and enemy might come from, otherwise they notice that they just kinda spawn.
In fact, the enemies where my gripe with the game. They are high polygon, very well known and spread around the internet. When I released
a game using them they where already often recognised as "FPSC models" and that was 10 years ago. They have since been used in OH so many low tier steam games and they don't go well with the atmosphere you created either. The axe brutes work in this environment but the straight-jacket monster and the tank seem so oddly out of place.
FPSC's AI is the monster playing a spotting animation and then darting towards you. Thats it, it has no pathfinding. Keep that in mind and try to not have furniture or boxes block the path of the monster.
As for the creatures, if this is your design choice, I respect that completely, but if you are interested, I still have a whole bunch of different low poly characters from the good old days that I can offer you. They would go better with the retro theme
in my opinion.
One last thing: Behind the retro shader are still the full sized textures! If you open the setup.ini you can edit that out by writing in:
Dividetexturesize = 2 or dividetexturesize = 4 (whatever looks better) That way your game will run even faster on lower end machines!
Last comment: The choice to remove the players arms was pretty neat but EAI's guns look pretty high poly. Have you tried the modelpack 5 guns?? Whatever looks better!
A bit more context would have been cool too but I see that you are already working on that.
This is a nice little project and I'm looking forward to more. Very cool.