Awesome! I've never seen a puzzle/speedrun/horror combination like this, but now I wanna see some more! My only feedback would be to have the monster move a bit faster, since once you've figured out most of the puzzle and you're trying to figure out the ending, you just have to wait for the monster to catch up. It was very satisfying to figure out the ending, and I had a great a-ha moment when I noticed that it seemed like the monster opens the door when it reaches it.