Rainbow Islands is an action & adventure game where Bub and Bob, now small boys, try to clean the Rainbow Islands of evil creatures. The two brothers must climb 4 levels on each island, facing a big boss at the end. They can trap enemies under their rainbows and jump on them to break them and collect colored gems.
Gameplay involves using the rainbow power to trap objects and then jumping on them to destroy them, while also collecting extra speed and rainbow power-ups. In two-player mode, Bub and Bob work together to overcome obstacles and defeat enemies.