About that multiplayer comment.. it would also be prudent to include a Heat meter of some sort, to limit the indefinite period of invulnerability effect of multiple consecutive slashes
Straw Hat Samurai has some great multiplayer potential!!! Think of the boss battle against the cyborg-ninja.. Being able to see the slashes your opponent makes and try to counter him! You could even add in some type of award system, like winning Ryo to buy items to change the appearance of your character. Bump this comment if you would like to see this happen