Brawl Brothers follows the story of Rick and Doug, or Hack and Slash, who run a self-defense gym in Bayside City. Three of their top fighters are also playable characters: Lord J., a karate and judo master; Kazan, a ninja; and Wendy, a pro wrestler. However, Dieter, a psycho villain, kidnaps these three fighters to clone them for his own evil plans.
As you control your chosen duo, you must fight through levels of cloned characters, each with their unique abilities, to reach Dieter's secret Air Fortress. The gameplay involves side-scrolling action and platforming, with an emphasis on combat and strategy.