Street FIghter II: The World Warrior is largely credited with creating the fighting game genre as we know it, and Champion Edition built on its success with refinements that made it more competitive within its genre, becoming the best-selling edition of the game. Champion Edition's key additions were the ability to play the four boss characters (Balrog, Vega, Sagat and M. Bison) and to play mirror matches with the same character, though it also updated some of the fighters' moves and added various balance tweaks and refinements to the game. Street Fighter II is considered by many to be one of the greatest games of all time, and the Street Fighter series is still among the most popular within the competitive fighting community.