One Piece: Unlimited Adventure is a role playing game based on the Japanese animé One Piece. When two of the pirates on board the Thousand Sunny ship confess to eating all food, the pirates decided to restock at nearby islands. When they accidentally stumble upon a magical island they loose their ship and the taste for hidden treasure rises.
The player takes on the role of of the eight pirates and can switch between characters at will. The pirates can attack enemies and plant life. Enemies drop iron and gunpowder, while plant life drops leaves, spices, wood and fruit. All these resources can be used to craft special tools such as a pick axe, fishing rod and butterfly net. These tools can in turn be used to find new resources.
The pirates have to fulfill various quests, for each quest certain resources are required, so it's up to the player to explore the world and find these resources. Often, combining resources will help the pirates to unlock new areas of the world. They can for example combine wood with liana to build a bridge. Food can be eaten to improve the characteristics of the pirates.