7. The Combo System - Street Fighter II: The World Warrior (1991)
http://www.youtube.com/watch?v=7cYJEvGUXAQ Street Fighter's combo system is such an inherit part of the iconic series that you can't possibly imagine it was ever supposed to exist without it - combos are Street Fighter, after all, right? Well, no, not originally, 'cause the whole system was invented accidentally by way of a glitch. Gosh, we're starting to think that most of mankind's greatest achievements have emerged completely by chance. Back when Street Fighter II: The World Warrior was getting itself made by a Japanese man named Noritaka Funamizu, he noticed something bizarre was happening whilst testing the game for bugs: during a punch timing, the game was making room for the possibility of second, third and fourth hits. Funamizu, either realising that he was an accidental video game genius or, like, feeling super lazy, decided to leave the glitch in tact. And that was mainly because he felt that the accidental combo thing was so difficult to get right that it wouldn't make a difference - nobody would cling onto it anyway. Wrong! The combo system caught on big-time and proved itself to be one of Street Fighter's most popular features. It was later refined for future installment, and the rest, as they say, is Hadoken. ... History. We mean history.