I like that there is a great variety of visible tools to use and two set of beautiful stones to collect. The tricky part is that you need to revisit two rooms for items that only appear after a certain task is completed. For example, the room where we start and the room where you find a knife.
Since there're sufficient clues provided, puzzles are easy to solve. My advice is to draw a route map on a piece of paper for taking notes. If you're stuck with a four-digit lock, translate DEAF according its alphabetical order. Also, a strange item is used on a book page to reveal a sequence. c:
Sound effect can be improved. I turned it off when I played the game to keep distraction to a minimum.