I already beat it. And in just 2 days after it fist came out. I'm wondering if i should take it back to Gamestop and get my +$60 back but i dunno. It is the best ninja/samurai game I've ever played though, but not even the games 50 stages contained me as i destroyed it.
I just found out that the single player mission, without xbox live, is a multi-player game in itself. Meaning the regular solo mission can be played with four different people.