Actually seems longer than I expected too, the first 7 battles only covered Part 1 of the movie, and I know it goes basically into the second season of the anime (I think, from some of the bosses I saw post the Mozgus battle), stretched out this could have probably 30-40 or more different battles in the Story Mode alone.
There's also an endurance type level, just non-stop floors of mobs while you try to get to Floor 100? I think with certain chars to unlock some of their different costumes (Femto, Apostle forms, etc). Plenty of shit to do really if you enjoy this type game. Still might not be worth $59.99 i'd say, but hey, I didn't exactly pay for my copy either.