Acclaim announced plans to release a video game based on 100 Bullets. However, following the collapse of Acclaim’s publishing house, the game has essentially been cancelled. It was intended that the player would be either Cole Burns or Snow Falls (a completely original character) and play in a third person view. The plot was generally unknown, aside from a supposition that it followed the plot of the comic book.
Later D3Publishing obtained the rights from Warner Bros. to publish a 100 Bullets game. They intend to make a video game completely independent from Acclaim’s aborted vision, but still heavily reliant on input and plotting from Brian Azzarello. Not much it currently know about the D3 version and it could have been cancelled too. [Infos from Wikipedia]