The moths' SFX are truly terrifying, it does a fantastic job at immersing the player into this dark castle. The feeling I had when I finally got the key, rushing to the door, only to get killed after a few seconds was amazing. I really like the sort of learning mechanic : there is no hint nor any path to follow, you have to learn in order to find the key. I think this is on top. The only thing I disliked was the very small light around the player (the smaller one, just around the sprite). I think it'd be better if you either completely remove it or make it a transition to the bigger light. The death animations are a cool detail too. Great job!