In We Love Katamari, the player controls the Prince, the 5-centimeter-tall son of the god-like entity the King of All Cosmos, who rolls around a "katamari", a magical ball that causes objects smaller than it to attach to it.[3][4][5] The player moves the Prince throughout each level, collecting objects in order to fulfill objectives set by his father. Collecting a certain number of objects causes the katamari to grow in size, allowing it to pick up larger objects that couldn't be rolled up earlier. Objects range from household objects like coins, pencils, and dice, to larger ones like buildings, mountains, and clouds. If the katamari collides with a moving object or a wall, objects attached to the katamari will fall off and decrease its size. Rolling against a wall allows the player katamari to "climb" it in order to reach higher areas.[3]
We Love Katamari differs from its predecessor in its level design. The standard game mode is "Make A Star", where the katamari must grow to a specific size as determined by the King.[3] New game modes include making the katamari as big as possible with a limited number of objects, rolling up snow to create the head of a snowman, collecting children and delivering them to a school,[6] and using a sumo wrestler to roll over food items to gain body mass.[6][7] Completing missions unlocks an alternative version of the level that features a new objective.[7] In most missions, players can find a cousin of the Prince which, when rolled up, can be selected as a playable character. There are also items known as "royal presents" that unlock clothing that the Prince and his cousins can wear. A cooperative two-player mode is available, where each player controls half of the katamari and must work together to roll up objects, as well as a "Battle" mode where players compete against each other to roll up more objects than their opponent.[3]