Though it is pretty short, I had a grand ol' time with this game. But even after getting all the achievements I almost didn't find the beautiful ending, so you might want to add an arrow in that room? I dunno.

Anyway this isn't that big of a deal, but in Nightmare Mode there's a small bug where, after you die, you sometimes can't respawn for some reason. Instead you can see more of the player character's skeletons falling from the ceiling and there's no other option beside pressing Escape. But yeah, pretty awesome game!