if you want to know what its like, imagine a mario like sound track, with help from Nobuo Uemetsu. In other words, unsurpassable. Aside from that, look at some screenshots with that music in mind, and thats what you get.

As for the gameplay, it is incredibly simplified when compared to say... Final Fantasy. You get a slot for Weapon, Armor, and Accessory, and they do things like you'd see in Final Fantasy. Prevent this status ailment, upgrade these stats, that kind of thing. Currency is in Coins or Frog Coins, items are arranged in an FF2 style arrangement, so you only have I think 30 slots for items, but you use them pretty often, so its not a problem.

Not much of a spoiler, but this is a rundown of the story.
(SPOILER)
The bosses are mostly not from the Mushroom Kindom, but from this other guy named Smithy, who stabs a massive (I mean, 50 feet or something) sword through Bowser's Castle. And he's broken the Star Road, and caused peices to shatter throughout the Mushroom Kingdom and beyond. Smithy is creating weapons, removing all wishes, and generally making a rather large nucance to everyone. Once you get to Rose Town in the second (third if you count Bowser's Keep) area, Geno will explain the whole thing.

And thats really it.