Ok. I'm going to give a very constructive review of this because this is an awesome but incredibly flawed game (so far, anyway).
I absolutely adore the fact that you managed to completely capture the aesthetic, quality, and feel of the original Spencer Mansion look in Full 3D. Not many developers have been able to do something like this. I don't know how you managed to accomplish that but I applaud you for it because I work with Unity and I've been trying to capture this style of graphics for a long while and haven't been able to figure it out.
I always wondered how RE1 could've been if it had Mikami been able to realize his original vision of the game being in first person before he had to go with the cinematic yet dare I say overrated fixed camera style due to technical limitations.
I also like that the characters have fully rendered shadows rather than just a circle shadow. This almost feels like I'm playing RE7, and that's a good thing because I love RE7.
Unfortunately, that's where my praise ends.
For starters, I couldn't figure out how to start the game. The menu loaded up and everything, but I could only use the WASD keys to navigate and I had to press "E" to do select.
You need to have some text on screen that display navigation controls, not only that, but there also needs to be a controls menu that shows you what the controls of the game are, because I ended up going into the inventory screen and not knowing how to get back out of it.
There is also no visual indication on how to pick up objects like the gun. I did pick it up but I was not sure of which button I pressed to do so because the game wouldn't tell and I was randomly pressing buttons.
The other thing is that the inventory menu doesn't pause the game. This is fine in a game like RE5, 6, and 7 where the world is still visible despite being in the inventory, but I ended up getting killed by a zombie offscreen because I was trying to figure out how to equip the gun in the inventory.
Also, one of your sound effects, specifically the outside area sound effect, has a discord ping sound effect that kept confusing me into thinking someone was contacting me on discord.
The other thing I would change, and I know this was in the original game but it doesn't work here because it's seamless in comparison, when you're in the main hall and you go upstairs, the music turns off. I'd actually change this because in the original the upstairs area was a separate section instead of a seamless area like it is here.