“button”
Read in 20 unusual control schemes on Gamasutra:
“Button: The simplest control possible, and by far the oldest given its use in pinball machines. It can either be pressed, or not. There are games that are controlled only by a single button, but that scheme mostly sees only specialized use. WarioWare Twisted has a mode where all the minigames are controlled by single button-presses. Buttons come in many forms: control panel buttons, face buttons, shoulder buttons and triggers. The PlayStation 2 has thumbstick buttons, which activate by pressing “in” on a thumbstick, and analog buttons, allowing the game to detect how hard they’ve been pressed. These days, analog buttons are most commonly seen on controller shoulders. The Gamecube’s primary controller famously featured analog shoulder buttons with a hard digital “click” when pressed in far enough.”