Street Fighter II: The World Warrior is well-known as the game that defined the fighting game genre. The vast majority of all mechanics used in modern fighting games began within Capcom’s amazing fighting game.
When the developers from the team sat down to discuss the development process for a new book — currently available only in Japan — they provided insight into many things about how the game was formed. From this, we learn that some of the character designs were given based on the results of Rock-Paper-Scissors, as well as opening up as to why the Four Kings — M. Bison, Sagat, Vega, and Balrog — were originally unplayable.
The interview has been posted on the Capcom Fighters Network, and has a lot of great information!