Rainbow Islands: Putty's Party is a single-player action platformer game in which players control Putty as he navigates through various themed islands using rainbows as his primary tools and weapons. In this game, the setting is a series of islands with distinct themes such as Insect Island, Monster Island, Doh Island, and Darius Island, each presenting unique visual styles and challenges. It stands out with its innovative use of rainbows for traversal, combat, and puzzle-solving, along with the requirement to collect gems to progress through levels, and features vertically scrolling gameplay on the WonderSwan platform.