Monkey Puncher

At the start of the game, the player must choose to play as either Kenta (male) or Sumire (female). While the choice has little effect on gameplay, the sibling who is not chosen is the one kidnapped. Shortly after the beginning of the game, the player is given their first monkey, called Freddy, to train.

After obtaining the first monkey, and any subsequent new monkey, the player must befriend it by offering it food before they can begin training it. Over time, the monkey becomes more and more friendly towards the main character.

At the beginning of the game, it is revealed that the main character's mother has died and that the player's father is a Monkey Boxing trainer who is kidnapped along with the main character's brother/sister (depending on who the player chooses to be) by the Saru gang of monkey gangsters. It is up to the player to advance through the Monkey Boxing Leagues to confront Saru and rescue the player's father and sibling. It is later revealed that they are being brainwashed into training and fighting monkeys for Saru. At first, Saru sends Cain after the player, who challenges the player to a Monkey Boxing Match.

After accepting the match, and defeating Cain's Monkey, Cain returns to the Mysterious Master of Saru. The next 'Boss' Character the player must face is the ROBO monkey, developed by Saru's Professor. Once these two have been defeated, and the player ascends to title of JSB Champion, they will receive an invitation to the Monkey 1 Grand Prix, held on Saru's secret island base. Upon defeating the 5 opponents, including rematches with Cain, and the professor, and battles with Sumire/Kenta, the player's father, and the Saru master, the game is essentially completed.

N64 Magazine gave the game a rating of 4 out of 5 stars, while the French video game website Gamekult gave it a rating of 5 out of 10.