Back in the 90's the arcade scene was in a slump without any real new great game coming out to rival the power of the NES.
Now there were 1 on 1 fighting games before but they were....not good. Karate Champ was okay, Street Fighter (I) was terrible. Then the occasional game that was one on one like Pro Wrestling on the NES.
Then it all changed. Capcom took the basic formula from the original Street Fighter and improved upon it in every way.
The controls and inputs were like butter compared to granite. The graphics were perhaps the best of the day when it released. There were now more characters to choose from ALL of whom would become iconic. The music was out of this world and took full advantage of the 32 (16?) bit speakers. With 8 characters to choose from Street Fighter II invigorated 1 on 1 PvP in a whole new way and popularized the fighting game genre, saving the arcade scene in the process.
Later, Capcom released Street Fighter II Champion Edition which was very similar to the original World Warrior but you could now play as the bosses who were unplayable in the WW, and you could both now be the same character. Some of the graphics like character portraits were cleaned up and some moves were tweaked too, like now a minor difference between Ken and Ryu.
Some FGC fans still consider SFII CE to be the best fighting game ever released.
Capcom would make later editions to the formula, add new characters and such and after many releases including SFII Hyper Fighting, Super SFII, and finally the sublime Super Street Fighter II Turbo.
"Super Turbo" is, in my opinion, the greatest game of all time. It took the gameplay from the wondrous SFII and perfected it. This game is very balanced when non-code input characters only are allowed. ST added Akuma in addition to Fei Long, Cammy, Dee Jay and T. Hawk from Super. ST also brought in "super moves" which could only be executed after filling in your super bar from attacking your opponent. The super move did furious amounts of damage and even had a KO effect if it knocked out your opponent.
30 years later, ST is still played in the FGC, in fact, some of its players are younger than it is. No other competitive game has experienced the lifespan of this game. No matter how you cut it, SFII is the best competitive game of all time.
