Really charming game, and the puzzles are very, very good too. I enjoyed it a lot!
I found a minor problem, which isn't a big deal actually. If you enter a room, exit it, and then enter another room, the key that you'll get there seems to not be the correct one. I found this when I entered a room I already concluded by accident. Again, not a major problem.
Once again, very good game. Cheers!