Final Blow is a boxing arcade game created in 1988 by Taito. The name would remain the same for all ported platforms, except for the Sega Mega Drive/Genesis versions, which renamed it to James 'Buster' Douglas Knockout Boxing featuring James Buster Douglas himself in 1990 immediately after his victory over Mike Tyson.
The game features a single season boxing championship run. You can select from a group of fictional fighters: Dynamite Joe - The Miracle Man, Fernando Gomez - The South American Eagle, Kim Nang - The Korean Comet, King Jason - The Black King, The Detroit Kid, The Invincible Black Panther.
The game is essentially a side scrolling boxing game where the player moves left and right to control a screen sized boxer. When the timing is right, the player can unleash a final blow punch which can sometimes KO the opponent in a single strike. The home versions contained a spectator mode where you can watch your favorite boxers compete.
The Sega Mega Drive/Genesis port was very close to the arcade counterpart in every aspect of gameplay, graphics and sound, with two additional boxers were added: James Buster Douglas (who was The Detroit Kid renamed and palette swapped) and Ironhead. A Sega Master System game starring Douglas was also released, but was not based on Final Blow.
The Genesis version was one of the key games used to market the Genesis console as part of the Genesis Does Campaign, particularly since Nintendo used Mike Tyson for its Mike Tyson's Punch-Out!! video game.
Source: Wikipedia, "Final Blow", available under the CC-BY-SA License.