Interesting concept, good art and sound design, and was actually really entertaining. Unfortunately, there is no reason to ever move your mouse, so it ends up being really easy. Three suggestions if you make more around this idea:
1. Make it so that the line between the player and their eye also triggers monsters
2. Add something you need to look at to open the door (not really sure what though)
3. Probably a bit complicated but mirrors and one way windows could be interesting
Regardless, you did a great job and I had a good time.