The mouse getting outside the game window, and putting full screen drop my fps make it not comfortable to play.
The audio: It fit well with what you done, it set an atmosphere, nice job for this. The visuals are ok.
Gameplay ( I know you've focus on audio don't worry): The random game-over is a problem, mainly because you can die fast, very fast you can literally die at the very first door, in few runs it happened 2 times. And actually the gameplay is to open doors waiting for the game-over screen, it's not very fun cause you don't really have control on your score.
All rooms are empty, with empty rooms and with fast random game over, it become very less scary cause you know already what will happen and less entertaining cause you know very fast whats behind the doory ou will open.. Adding sometimes suprises like sounds, items or monsters would be more fun.
When the door hand is in the right side the door open player side pushing him. I suppose you have only one animation for the door and that's why it happen depending of the side you come, but it would be better if everytime the door opened at the opposite side of the player like if he was pushing it.
Well overall, not bad for a first time in 3D.