This is what a portable Brawl game should be.
Graphics 8,5/10: The game shows great colors in it's scenarios, being many of them interactive( in PS 1) and vivid (in PS 2), with plenty destructive things to be grabbed tossed and so on in the middle of the fight. The characters have a nice oriented movesets, also having goodlooking and cartunish style, making the real aspect of the game so bright: FUN. Is quite nice to see the scenarios and so while picking up a truly mess around on the screen, that's perfect fit for the portable.
Sound 9/10: Not only the narrator is quite cheerfull in both game's presentation and narration, but also you hear the many background sounds and special effects quite distincted one of another. There's mostly a big pandemonium in the game, hence it's nature, but the effects fit it well, very well I would said.
Gameplay 8,0/10: It's a brawl game, where you pit your character against another, each using a unique set of moves that fits their design, and each very distinct on itself. You start battling around screen having full axial control over your char, beating the opponent in your ways. In the PS1 only 1x1 matches to fit the stuff, wich is already much fun, but in PS2 you can have your very own personal party with any combination of 4 fighters (1x1x1x1; 1x1x2; 3x1; 2x2) and this brings great stuff. Also in PS2 your scenarios have mini-games inside, like one moment you will be facing your oponent, in other you both will be running for your lives as a giant boulder will force to do so. Also the controls fit well, they're well mapped and allows to perform combos, and since your "objective" in game is to collect the powerstones in the middle of the fight, your character changes temporarily to an upgraded form with another powerfull moveset. The gameplay overall is amazing, the only major flaw is about loading times, specially in sharing the game, takes quite alot to wait for loading, but if you can bypass it, it surely worth the time.
Replay 8,5/10: There's some content (artwork and alike) to be unlocked, but believe me when I said that this really isn't the motive that will make you replay the experience in the portable. There's tons of fun in brawling inside the game, and will make you want to tray more in many ways, including the in-game boss fights. It's really enjoyable.
Overall 8,5/10: Powerstone collection is a really nice and fun game. It brings back memories for those who already played on Dreamcast, and nice experience for those who seek a fast paced action in a few bucks, that, despite the loading time that CAN be sometimes a bit too pushy, in overall is a nice port and portable fun for those who couldn't play Smash Bros(Actually, in terms of gameplay I prefer PS over Smash, BY FAR)