Quick Note: For fans of One Piece, there isn't a better adaptation of the tone and feel of the characters and the world. The combat can get stale outside of boss fights, but between the all new story, the ability to play your favorite pirates, and the extra content there's plenty of game here. Never heard of One Piece? You probably should stay away.
Anime translations to games don't always work out the way fans want them to. You would think that taking the impossible battle sequences or outlandish powers and bringing them to a medium where players can interact with them would be simple, but often times the transition leaves behind something special, making the game feel like it's glossed with the anime inspired coat of paint, but missing the heart of the source material. One Piece: Unlimited World Red is the opposite: as an adaptation of the anime/manga, it feels and looks amazing; as a game, it leaves me wishing there was just a little bit more there.