The Sega Genesis controller was only a mild upgrade from the previous Sega Master System controller. The Genesis controller added one action button and a start button, for a total of three action buttons, start, and a D-Pad. Later in the 16 bit era, Sega released a version of the controller with six action buttons, likely in response to Nintendo’s six action button SNES controller and the demands of arcade games ported to the console. Street Fighter II on the Genesis could not be paused with the three button controller because start was used (awkwardly) to switch between kicks and punches, leaving no button for pausing. The later controller also added a Mode button to switch compatible games into six button mode.