The game is known to be quite short: once a coin is inserted, a circular-shaped punching bag will emerge from the cabinet. The player puts on the attached boxing gloves and tries to hit it as hard as they can. Once hit, the scoreboard will calculate how hard you hit the bag. The bag will then emerge again, and will repeat the process. After the second round, the game is over, and tickets will be awarded to the player based on how hard they punched the bag twice.
Knockdown '90: First sequel to Knockdown from 1990: has more rounds. Knockdown 2001: Second sequel to knockdown from 2001: has multiple game modes and a new punching bag.