Besides what Akira already said:
Guardian Heroes: Hmm.. ok, this is a fighting game, but it's completely different of all you've seen before. It's a hybrid of an RPG and Streets of Rage, with AMAZING, OUTSTANDING 2D graphics, and action like I have never seen before, 6 simultaneous players (if you have an adapter), and it throws more things on the screen than a shoot'em up! If you can find this game, snap it up!
There's a game I only saw, never played, but it seemed to be great: Silhoutte Mirage. And it's from Treasure, so you can't be wrong with it