Rainbow Islands Evolution is a single-player action platformer game in which players control Bub and Bob as they navigate through colorful, vertically scrolling levels, utilizing rainbows as both a weapon and a means of traversal. In this game, the storyline revolves around Bub and Bob fighting against an evil recording company that pollutes the Rainbow Islands' environment with disruptive musical noise, threatening the flora and fauna of the region. It stands out with its innovative use of a hurdy-gurdy as a weapon, allowing players to create rainbows that serve both as platforms and attacks, and the expansion into a third dimension with accessible background platforms adds a new layer of depth to the classic gameplay.