How long is this game? I plan to rent it. Can you finish it in 1 week?

I just got this game for the Gamecube, but haven't finished playing it yet.

From what I've heard, this game can be beaten in about 10-12 hours by REALLY skilled players. I even heard some people complain about how short they felt it was, but it's the difficulty of the challenges that extends the playing time for most people.

I think that if you can play if for a few hours a night you could beat it with a rental.

Any opinions from someone who's actually beaten this game?

Took me around 30 or 40 hours to beat. I heard they toned it down on PS2 though.