In the near future, the world has been ravaged by nuclear war. Cities have turned to rubble, and only disparate pockets of humanity yet remain. Ruthless gangs clash for control of precious food and water, and prey on the weak to show their strength. One man walks the wastelands, righting wrongs, destroying evil, fighting for justice and lost love. His name is Kenshiro, successor to the ancient art of Hokuto Shinken -- the Divine Fist of the North Star.

Fist of the North Star is an action game based on the iconic manga from 1983 by Buronson and Tetsuo Hara, and is part of Koei's long-running Warriors franchise. The player controls either Ken or one of his many allies and enemies in one of several game modes.

The main attraction is Legend Mode, which follows the story of the original manga. Unlike most Dynasty Warriors spinoffs, this mode pits the player as a lone warrior -- sometimes with one or two allies, but often alone -- against waves of thugs, fighting through wastelands and destroyed cities to reach the boss at the end. There are seven missions in each chapter, which include varied objectives like defeating a group of enemies within a time limit, reaching an area before enemies arrive, or protecting a group of defenseless villagers. Each chapter culminates with a boss fight at the end, who must be dispatched by using one of the character's signature moves.

Additionally, there is also Dream Mode, which presents a series of "what if?" stories for each character. Dream Mode missions take a more traditional Dynasty Warriors-style approach, featuring large, open maps filled with enemy and allied armies, bases to capture, and changing conditions as the battle progresses. Dream Mode can, unlike Legend Mode, be played two-player cooperatively. Any unlocked mission can be played with any character, though only completing a mission with the designated character will unlock the next mission. Completing Legend and Dream mode stories will unlock new characters to play as.

As the player defeats enemies and completes missions, karma points are earned. If enough karma points are earned, they turn into skill points which can be used to purchase upgrades for that character. The upgrade system uses the "meridian chart", where numerous spheres are aligned in a grid. Starting from the center, the player can only purchase upgrades that are connected to any other upgrade that has already been purchased. Upgrades include simple enhancements to strength and health, slotted skills and attributes such as attack attributes and faster karma gain, and even additional Signature Moves -- up to eight for each character.