King of Fighters: Extreme is a mobile chapter in a long-running 2D fighting game series that first appeared in 1994. N-Gage version follows the most rules and has the most features of the arcade game. There are twenty one character to choose from to battle CPU or a human opponent in several game modes. Graphically it's not as richly detailed as arcade or console versions, as backgrounds lack animation, sprites in this version are much smaller as well as there are black bars on top and bottom of the screen to make game screen look wider.

Among the game modes there are practice, survival, story and a battle which is a versus mode played via Bluetooth. Story lets you play through the ladder ending with a boss with three of your chosen brawlers. In tradition of King of Fighters, you don't go in a fight alone, but choose several characters, where after defeat of one another goes into the arena. The opposite party also got several brawlers at hand. And by pressing a button you can summon your backing character to help you a little bit mid-fight.

Every character has their own martial style and set of special moves. There's also a "max" move, where one first needs to fill up a meter, scoring hits to use it, that's in turn lets you unleash a series of powerful attacks. The list of key combos could be handily summoned at any time by pressing pause, as well as controls could be redefined even in the heat of battle. All of the basic moves could be accessed by pressing assigned buttons due to N-Gage twelve-key phone keyboard.