This game is fun and challenging, as the levels you'll play are a mystery, and you need to plan ahead in order to do really well. However, there's an issue with the lock system. For one thing, defeating enemies won't always lower the number of locks (I'm not sure whether this is because there were actually more locks than shown by the counter, or the game doesn't register defeating the enemies). Also, I've noticed that every time I select "retry" after losing, instead of "back" and then starting a new game, the stairs never unlock, because the counter never hits 0. Please look into these issues. The game is still fun, but they're rather annoying.