One Piece: Grand Battle is based on the Japanese anime of the same name and is actually the fourth game in the Grand Battle series. This installment features cel shaded graphics, 14 characters in total – 5 playable and 9 that you have to unlock – and has 5 modes for you to play and 2 others where you can view unlocked art of the characters.
The Grand Battle mode is where you can fight against human players or CPU players and has most of the characters unlocked from the beginning.
Story Mode is where you’ll spend most of your time since this is where you can unlock the rest of your characters and other staff like screenshots of the anime.
Mini Games, as the name implies is a mode for playing mini games. Usopp Pirates challenge you to a series of 3 mini games. You begin by selecting three players for your team and each time you win a game you can select a member of the team that lost. Of course the opposite can also happen if you lose a game.
Grand Tourney is a multiplayer battle tournament where you can set up to 16 human or CPU players to compete.
I believe Training mode is pretty much self explanatory.
And there are also 2 other modes – Treasure and One Piece Art. Basically this is where you can find all the staff you have unlocked like character endings, costume art and staff like that.
Characters have basically the same button presses to perform attacks. Other than that each one has a support character that he can call to aid in the battle and 2 different unique attacks that can be used if certain conditions are met. There is also another unique attack for each character, with a long animated sequence that if you use when low on energy the enemy can be defeated with only one blow.