Joe & Mac: Tatakae Genshijin is set in ancient times where two cavemen ninjas, Joe and Mac, must fight their way through enemy tribes to rescue a group of girls who have been kidnapped. The story follows the duo's perilous journey as they navigate through treacherous terrain and battle fierce foes.
The gameplay involves controlling Joe and Mac as they jump, club, and throw various objects at enemies to clear levels. Players can use a range of weapons such as boomerangs, bones, fire, flints, electricity, and stone wheels to take down enemies from a distance. With multiple levels and challenging obstacles, Joe & Mac: Tatakae Genshijin requires skill and strategy to progress through the game.