This is by far, the best rpg on the gamecube
It plays very much like a final fantasy (7 & 8 spring to mind more than others) where you control one character through an amazing story with many twists (some minor things in the game have definately been ripped from the final fantasy series, but this is a good thing.) The plot is good but not great, sometimes you can tell what is going to happen before it does but this just makes the twists better as your not expecting them at all. Basically you take the place of a young man escorting the Chosen one on a journey to regenerate the world.
The gameplay is just like final fantasy's where you control one main character, build up levels, collect items, meet new party members and the only difference between the rpgs is the fighting system. Where in final fantasy, endless battles soon become a chore this doesnt really happen here. This is because of the excellent fighting system employed which lets you control your character in battle and actually fight and you'll soon be WANTING to fight just to pull off massive combo's. Also there are no random monster battles, you can choose to fight whoever you want although its not a good idea not to fight anyone.
The game starts off really hard as well if you just go in button bashing and you'll soon learn to time your attacks better, use magic more and basically become a better fighter, but then as you progress the levels you'll see that you dont really need to do all this as the game gets progressively easier rather than harder and you can go back to button bashing without being punished for it.
This i would say is the biggest fault with the game and there are a few more, the puzzles in the game are hardly what you could call challenging, there are also an annoying feature in the game called skits where you sit through (usually a 2 minute break) to watch a few faces on screen talking (no sound) and you cant skip lines after you have read them.
But this is basically it and thanks to the gorgeous graphics (cell shaded), final fantasy esque sound and brilliant gameplay, they seem pretty insignificant, and this is most definately the best rpg on the gamecube and one of the best rpgs made for any console this decade