The graphics look nice, but the unbalanced gameplay and the inability to link combos leads to another bad anime game.
Now, the best part about this game is undoubtedly the graphics. The cel-shaded look of the game fits the series extremely well, and the character models, while definitely leaning towards cutesy, look top-notch. All the attack effects are a sight to behold, and you will probably find yourself pleased with the shockwaves and smoke trails of the various characters. The camera, surprisingly, is almost never placed wrong, and you will always have a clear view of your fighter. While there is sometimes some slowdown and the relatively small fields sometimes feel a bit cluttered, all in all, this is certainly the main draw of the game. Unfortunately, the game underperforms and fails to satisfy in nearly every other way. The sound is just about passable: The background music, while never excruciating, can get very repetitive and annoying after a while, and don't even get me started on the character voices. Case and point--"It looks like you might have some spunk!", "You're taking on me!", and my personal favorite, "Who are YOU? What are YOU looking at?" Gah. The gameplay, unfortunately, is just as bad. While it does most closely resemble Power Stone in the style of the game's fighting, this is the most horrible imitation of Power Stone I've ever seen. While there are technically combos in the game, there is absolutely no way to link them together, and the movelist is so small that you may well find yourself repeating the same moves over and over and over again just to get it over with. On the positive side, all your favorite moves and characters from the series are here, and all of the attacks are nice and flashy. On the flipside, there are only 8 tiny stages that all claim to have some sort of interactivity. Bah. All the interactivity is so lame, it's hardly even worth mentioning. For example, on one of the stages, you're boxed in by police barriers in the form of a circle, and you adjust the shape of the police barriers. You know what that means? You can turn the circular field into an almost-a-circle field! Oh, joy!
Gameplay:6--My God, this is disappointing. All of the combos have no depth whatsoever (O-O-X, X-X-O, O-O-O, X-X-X, you get the picture), and you can't link them together. You're just stuck doing the same moves, over and over and over again. Oh, look! A super move! The stages are tiny, and any hint of interactivity simply gets lost in the void of mind-numbing repetition. The only upsides are the roster of characters and the flashy attacks.
Graphics:8--The only place where this game excels. It all looks almost stunning, and everything about the graphics are perfectly tailored to the anime/manga. However, there is some pretty bad slowdown when the fighting gets hectic, and sometimes the levels just seem to get too cluttered.
Sound:5--I could describe this in one word: Bleh. But since I AM writing a review, I'll go ahead and detail just how bad it is. Nearly everything the characters say sounds absolutely horrible, and the rather repetitive background music doesn't help the situation at all. Even the decent menu music fails to impress.
Value:6--Well, there really isn't much to do here. There's a small selection of modes that will not satisfy on almost any level, and the lack of depth and stages will eventually bore you. There is one redeeming factor, which is the rather expansive art gallery, but I'd gladly omit that for a bit more variety.
Tilt:8--As hard as I've hit this game, it will most surely please the people who love One Piece, and while I can't claim I really LOVE it, I do certainly enjoy it, and this game does please me in that sense. It's good to play as your favorites from the anime/manga, and the stages all bring up a key point in the series where a climactic battle took place in any given story arc. It's just too bad most of the rest of this game sucks.
In short, this game will please the fans, and only the fans. It's really sad, too, because I could see the beginnings of a fun game here. Pick it up if you really like the series, but if you don't, there are much better games you could be spending your money on.