You can buy this game right now. It's called "Mystic Heroes" on the GC and "Dynasty Warriors" on the PS2.
Seriously, it's the almost the exact same game, right down to the power meter for special attacks, and the fact that arrows are your character's worst enemy. As near as I can tell, all they added were item upgrades which you can equip and an opening FMV.
This game type is always fun for the first couple of hours, then rapidly becomes boring as the repetition REALLY starts to sink in. Good for a few hours of mindless fun, but I'd recommend renting instead of buying.