Cool Ball is a puzzle game where the player controls a bouncing ball on the GameBoy. The story follows the ball as it navigates through increasingly complex levels, collecting points and avoiding obstacles along the way. As the ball progresses through the stages, it encounters various hazards such as sticky platforms, angled surfaces, fires to put out with water drops, and walls to destroy with a hammer. The ultimate goal is to reach the exit key in each level to unlock the next stage.
Gameplay involves bouncing the ball around the screen, using the tools collected to overcome obstacles and stay on course. The player must time their movements carefully, as some platforms are stationary while others move up and down or side to side. With a combination of skill and strategy, the player can collect as many points as possible and progress through the game.