I love the art style and the idea!
So, as far as I understand from the other comments, you didn't get around to adding clues to the game? That's really unfortunate, as it kinda breaks the entire gameplay... After the castle scene you can't really see any other content, just because it's kinda impossible to just brute force the 5 key puzzle.
Still, this seems to be a great game as soon as some things get finished. Also, I love the lore implications of the game. Why is Cucho here? And why is he tethered to a heavy weight, keeping him in this room? And who are we?
Oh my god, this is way to interesting of a game concept! :D Really hope you finish it after the jam.