Solid voice acting, terrific fan-service, and innovative gameplay make this game one of the best anime-based videogames.
One Piece: Unlimited Adventure is a huge step up from Grand Battle and Grand Adventure, both fighting games released in the past couple years. Unlimited Adventure is, as the title suggests, an adventure-based game. You're on an island and travel between different "zones" of the island, all with different enemies and items to collect.
The gameplay is really solid. The nunchuck is used to move your character, center the camera, dash, and to lock-on to nearby enemies. The Wiimote is used to use items and attack. Thankfully, the Wiimote's motion isn't overused in this game. You only use it to swing the net, fish, and for one or two attacks. The controls are very responsive. The one aspect of the gameplay that falls short is frame-rate. When the screen is littered with enemies, especially in the Spandam boss battle, the framerate takes a steep drop. Luckily there aren't too many times this happens.
The graphics are beautiful and rank just below Mario Galaxy. The characters are full of life and have many different expressions they show. Something that confuses me a little is when you're looking at enemies far away, there's an illusion that makes it look like double-vision, kinda like casting a shadow of the enemy next to itself. It's confusing and questionable why this little effect happens, but I digress.
The music is pretty catchy, though it is slightly disappointing that there's no music from the show, not even the theme song. All the voice acting is very solid, even for those character not introduced in the series yet. It's apparent that the One Piece voice cast has gotten perfectly into character.
There is so much content in this game that it's unbelievable. First, there are so many character to choose from in Vs. mode. FUNimation is doing an excellent fan-service to everyone in love with the series by keeping ALL content from the japanese version of the game. That means all characters, weapons, and items that haven't even appeared on television in the US have been kept in the game (unlike Grand Battle), so there's no need to import this game. Second, there's a lot of collectibles. Throughout the game, you keep a log of bugs and fish, so collecting them is pretty fun. You can also try to break your record of the biggest bugs or largest fish. Third, each Strawhat has 3 costumes. After you beat all the bosses for the first time, you can start making other costumes for characters and use them in single-player mode.
Vs. mode is fun, though lack of wifi is disappointing but understandable. Vs. mode is actually quite balanced and uses a point-system, very similar to Dragonball Z: Super Sonic Warrior 2's Vs. mode. You can choose between a 8 point or 16 point match, and each character you choose takes up a certain amount of points, 5 being the largest point value of a single character. You can play as any enemy you've encountered in the entire game (except for a certain pirate enemy), which is nice because a lot of them are worth 1 or 2 points, which can help to fill in the games of your Vs. mode team if you have a few points left.
Overall, One Piece: Unlimited Adventure is well worth the wait. It was announced all the way back at E3 2006, so it's great to see the first tru adventure game on the way since Legend of Zelda: Twilight Princess. Whether you're a fan of One Piece or not, I'd recommend this game to any adventure game fan.