The player controls Bubby or Bobby across seven islands made of vertically arranged rounds. The objective is to climb upward, defeat enemies with rainbows, collect fruit and power-ups, and reach the goal before the rising water catches the character.

A rainbow can be created horizontally, used as a platform, or broken to attack enemies below or above it. Collecting large diamonds in the correct color order can produce valuable rewards, while each island ends with a boss encounter. The NES release is primarily a one-player game; its exact multiplayer behavior differs from the arcade version.

Use rainbows as temporary platforms rather than treating them only as weapons. Build a rainbow across a gap, jump onto it, and break it when an enemy is positioned underneath. This is especially useful on the narrow vertical routes of the later islands.

Prioritize safe climbing and diamond collection over unnecessary enemy chasing. Watch the water level, learn the location of power-ups, and approach bosses with room to jump; a missed platform can be more dangerous than a single enemy.