This is a good concept and has an interesting monster that leaves me wanting to know more. having said that, after finishing the first night, I think a few things can be done to improve the experience.
Improvements
- If there are multiple nights, it'll be good to reduce the number of rooms to enter OR the number of items, otherwise it'll just take too long for each night and ultimately end up boring the players
- The movement speed can be improved. Assuming the monster is stationary, reduced movement speed or lack of running is unnecessary
- Lost item to be more visible, though probably it might just be me that can't see properly
Otherwise its a great start and I look forward to more updates in the future.