If you've ever played Power Stone, you've essentially had a tutorial in how to play Rave Master. Based on an anime series of the same name, you're playing another in a long line of anime series titles that wrap a text based story around a relatively simple game that is possibly good, possibly bad. In this case, I'll tell you up front that this is what I'd call a very weak Fans Only rating, as it's assembled much like a unique Lego creation that you built from the remnants of the Millennium Falcon crossed with a Pirate Galleon. It could've been good, but it basically turned out pretty ugly.
The fighting is from a detached camera angle that shows you both characters as you wander around the stage, which is usually a fairly square patch of ground, littered with various breakable objects. Weapon fighting is the name of the game, and in addition to your character's signature weapon, you'll also collect Rave Stones and Shadow Stones, each of which enhance your character, giving you special abilities. In addition to the stones, you'll be able to disarm your opponents, and if you so choose, pickup their weapons to fight with, along with anything else you can find lying on the stage. Although this at first sounds interesting, the weapons in each category (hammer, knife, two handed sword, etc.) all tend to play as if they were the same weapon.
Combine all of this with an upward climb of increasingly difficult opponents, and I don't think you'll find it that enjoyable of a game to play. In particular, the steep angle of a learning curve in Rave Master tends to leave you getting beaten regularly after just a few matches, until you can gain the necessary skill to thump the computer. As it doesn't seem intent on providing that good of an environment with which to learn the game initially, I found this aspect of the game rather unrewarding.
Finally, everything that happens in between the fights is presented as simplistic cutscenes and dialog, in the traditional portrait/text format that you can find in other anime styled games. As for the look of the actual gameplay itself, it definitely isn't pushing the Gamecube's capabilities, and is only good in that there's nothing overall terrible about the graphics. As there's little in the way of decent voice acting, and a generic soundtrack, I found listening to this game about as fun as looking at it.
Final verdict? It isn't a bad game per se, but I'm relatively certain that it's only going to mean something to Rave Master fans, otherwise I'd suggest you pass.