I think the difficulty curve is off. I beat Mandarina in one go but Ghost has 3 new gimmicks (so far).
Plus, the main mechanic is hard to begin with. I can't see the shurikens turning black and so have no idea how close they need to be for counterattacks.
The powerup mechanic seems pointless as it can be worn down but hits, so it's just a faster way to win as opposed a chance to turn the tide.?