One Piece: Aim! The King of Belly is a Japanese only game for Game Boy Advance. This game takes place from the first arc in the story up to Alabasta Saga. The game is simply just a board game, with additional aspect of traditional RPG Game.
The Player controls one of the five playable character (Luffy, Zoro, Sanji, Usopp, and Chopper in a board game based on One the One Piece world. From the START Point, the players, with their boats, move around a vast seaboard without any guide. Because there is no GOAL point at any turn, movement is decided by rolling a die, or additional dice if one gets a card. The goal of this game is collect as much money (Belly) as Nami wants for the crew.
To move and find new islands, players roll a die. If it lands the player on a sea platform, the player will pick up a card. The cards carry various effect, such as healing HP/MP, change your direction, fight monsters and give you additional dice the next turn.
Along the way, players will find islands, guarded by villains from the One Piece Story (both manga and anime villains). Players will be given options to fight them, or to try and escape. If they choose fight, the player will engage the enemy in a classic RPG fighting game (one attack allowed each turn). When the player wins, they are awarded with some treasure, and money, and sometimes a Shop, Restaurant or Workshop will be built on that island. Sometimes an island contains only treasure without being guarded, and sometimes players will meet allies for battles there.
Player status include HP (Hit Points) for life value. If the players runs out his HP, players will be knocked back to the START point and lose some Belly. MP (Miracle Points) are used to perform special moves and attacks. MP also can be used out of battle. On the board, players can perform special moves, such as Luffy's Gomu Gomu Rocket to increase his dice number by 2. MP will regain itself slowly during each turn. Items can be put into your inventory, though you can only carry 5 different items at one time. Items in the One Piece world include Meat for HP, and Mushrooms to lower your enemy's status. The items can only bought in Item Shops at some islands. The number on the dice represent your movement each turn. Dice can be upgraded in workshops. Each character have their own type of movements however.
- Mohji and Richie
- El Drago
- Don Krieg
- Alvida with Sube Sube no Mi
- Bear King
- Honey Queen
- Boo Jack
- Pin Joker
- Skunk One
- Mr. 5
- Miss Valentine
- Mr. 3 and Miss Goldenweek
- Mr. 4 and Miss Merry Christmas
- Mr. 1
- Miss Doublefinger
Some characters will join you if you meet them on an Island, or by picking up Special cards. Allies will fight with you if you summon them. They can only be summoned once, last for a battle, except Mr. 8 and Pell as Vivi's special, they can be summoned many times in battle as long as Vivi's MP remains.
- Usopp Pirates are the weakest ally, deals damage 10 x number of dice. Recover the HP of the summoner when they are defeated.
- Johnny and Yosaku
- Dorry and Brogy are the strongest allies with max HP 9999.
- Nico Robin recruited when picked up field card Nico Robin. Roll a cube dice after pick up the card, she will join you when 4~6 appeared. She is the fastest ally with max speed 255, and she will recover 999 HP every turn.
- Portgas D. Ace will recover 300 HP every turn.
- Mr. 8 appears as Vivi's special, 25 MP for one time, he will recover 300 HP every turn.
- Pell appears as Vivi's special, 60 MP for one time, he will recover 300 HP every turn.
- Nami appears to act as a "money bank", if the player meets Nami, they will give half of their Bellies to her so she can prevent those Bellies from trading, curing after failed battle, etc.