Maybe I missed something, but I couldn't figure out the first puzzle. I found two numbers but couldn't find a third. But that's probably a personal failing, not the game.
The atmosphere was fantastic. The environment and the sound design were a good fit for each other.
The mouse sensitivity was a bit high for my liking and it would be nice to be able to tell exactly where the player is looking instead of a vague "middle of the screen".
Great work!