Hamtaro: Rainbow Rescue is an action-adventure game where players control Hamtaro and his friends as they try to gather the seven colors of the rainbow. The story follows Prince Bo, who fell off his rainbow, and needs help from Hamtaro and friends to rebuild it.
The gameplay involves completing various mini-games throughout a colorful world filled with talking hamsters, each with their unique specialities. By winning these mini-games, players earn stickers and pictures that can be used in the game's virtual stickerbook or traded with friends using a GameBoy Link Cable.