I WANT MORE
Aesthetics are great, love unfiltered textures. My only gripe with it is that the contrast is too high or something, maybe too much ambient occlusion too. Some dark things will bleed into a black blob, played with the monitor on the highest brightness but it didn't help much. Some examples of what I mean:
Options menu of course, the default mouse sensitivity was really high on my computer.
The slow transitions between rooms can be a bit annoying, I can see what you're going for with having them though so maybe its necessary. I wish the doors would stay opened though so you can better tell where you can from when the corridors look similar. Designations above the doors would also help, eg. "DV-023" etc.
Key prompts while inspecting objects would be nice; <A | D>
The revolver is great, although aiming at a distance can be hard. But that might be the point. I couldn't see any point in spinning the cylinder though, I think I'd prefer if pressing R would load a bullet only into the top chamber and you had to spin it manually for each bullet. Also didn't see if you could unload just one bullet, pressing the unload button could unload just the top bullet and holding the button would empty the entire thing.
Loading a save doesn't say which slots are filled.
At first I thought I had to enter the temperature into the device with the key and tried to find a way to do it. Realized it had already been done, you could add a snippet about waiting for the red light to turn on so its obvious. I mean its the first puzzle right.
Should you be able to use the metal hook in melee too?
I think the sort of SCP/Half-Life/Resident Evil think you're going for is really working, excited to see more from you.