In Kaboom!, a "Mad Bomber" is dropping bombs to watch them explode.[4] The player starts with three buckets and must control water-filled buckets to capture the bombs to defuse them and gain points.[5][4]
The game uses the paddle controller, moving the buckets of water left and right by moving the dial clockwise and counter-clockwise.[5] The more bombs collected leads to the bombs being dropped faster.[4] When the player misses a bomb, all other bombs on the screen explode and the player loses one of their buckets. If at least one bucket is missing, the player will receive a new bucket every 1,000 points.[5]
The switches on the Atari 2600 console can alter the game. Difficulty switches on the console make it so buckets only appear half their width, making grabbing bombs more difficult. A two-player option is available, where the players take turns controlling their buckets and have their own individuals score on display.[5]