If you were to ask any serious video game enthusiast about which game they consider to be the king of fighting games, 99.9 percent of the time you're going to get the same answer, and here's a hint, it's not going to be the one with the word "king" in the title.
For almost two decades, the Street Fighter 2 line of fighting games have dominated the genre. Their easy to learn yet difficult to master nature has kept them relevant throughout the progressing years of advancing technology; and while modern fighting games have moved into 3D, gotten larger, and became much more complex; they never trumped Street Fighter 2's package of simple mechanics and infinite levels of mastery.