The adventure part of Captain Rainbow is set on enjoying the Island Life together with the other islanders. Nick can go fishing, bug catching and help the other Islanders with their requests. Most of the request can lead to various mini-games, such as boxing and golf.

The action part is based around those crystals. If many Kirarin are collected, a star will fall from the sky. The star can be carried to an altar at the top of the Island where it will grant a wish. While carrying the star to the altar Nick is challenged by a mysterious silhouette who for unknown reasons wants the star for himself. If Nick succeeds in bringing the star to the altar there will be two choices left for him. He can either grant his own wish to become a popular hero again or grant the wish of one of the islanders and go back to finding other Kirarin.