This was incredibly fun! It's basic but it gets to the point and it makes the player work a bit. Nice atmosphere, a simple and solid core gameplay loop, and I'm excited to see more about what happens in this one.
A couple of bugs/issues I encountered:
You can apparently only interact with the stone dials in the center at certain angles, while crouched? It was very difficult to use.
The camera flash seemed to not work on the Duke on the main floor.
The flashlight washes out the lit area when it's up close, it's because of how Unity handles lighting. I've had the same thing happen in my own projects.
Great job overall though, and I look forward to trying out the full game!