Sutte Hakkun GB

On an island far away in the ocean, the "Peaceful Islands" used to stretch above the land. One day the rainbow mysteriously broke apart, separating into shards that fell on the land, which is divided in four islands. Eager to return the rainbow to its magnificent self, Hakkun sets out to retrieve the shards.

Résumé

Sutte Hakkun GB is an unreleased game for the Game Boy and Game Boy Color, compatible with the Super Game Boy.
Both this game and Sutte Hakkun (an earlier cancelled Sutte Hakkun Game Boy port) were found in the Nintendo Gigaleak in 2020.

The game has different levels when comparing to the previous versions.