I would say don't bother. I think it's one of the worst games ever made (yes, I know some people will disagree with me here, but fuck it).
Honestly, you're better served watching all the cutscenes in a row on YouTube than you are playing it (as in this: Final Fantasy XIII - The Movie - Marathon Edition (HD) - YouTube (
http://www.youtube.com/watch?v=yxMcuzOgVrU)). It makes for a MUCH better movie than a game. Below are some other good reviews of the game (the ZeroPunctuation is accurate as well). Don't spend your money on it.
Socksmakepeoplesexy.Net - We're A Fighting Game Community Website! (
http://socksmakepeoplesexy.net/index.php?a=ff13)
Final Hallway XIII - JonTron - YouTube (
http://www.youtube.com/watch?v=47YPs-qwNQU)
http://spoonyexperiment.com/category/game-reviews/final-fantasy-xiii/