In Bust-a-Move, you play as a device called "pointer" that moves around the bottom of the screen. You aim and release randomly colored bubbles upwards, trying to make them touch identically colored ones. If they do, they'll pop and disappear from the screen. The goal is to get groups of three or more bubbles to form before the opponent does.
Gameplay involves using your pointer to control the direction of the bubbles, bouncing them off the walls if needed, and carefully planning their trajectory to make them touch other colored bubbles.