Those two circles on the side, usually the places where a joystick sort of thing goes, have been replaced by grooves, like the thumbsticks were blasted away by the world's tiniest meteories. The grooves are touch-sensitive trackpads, so to pilot your way through a game, you rub the grooves. The buttons on the controller are in the center, a departure from about every controller that's ever existed, which consistently relegated them to one side. (Makes sense: many games on Steam were built with a PC in mind, where action is controlled through a mouse and keyboard. The trackpads could offer functions that would be impossible using traditional design.) Rather than "rumble" functions, where the controller vibrates according to something that happens on-screen, Valve is employing "haptics." In their words, from the announcement page: "The Steam Controller is built around a new generation of super-precise haptic feedback, employing dual linear resonant actuators. These small, strong, weighted electro-magnets are attached to each of the dual trackpads. They are capable of delivering a wide range of force and vibration, allowing precise control over frequency, amplitude, and direction of movement." In the center of the controller is a touch-screen--players can cycle through a menu to, say, select a game, then click (it's based on clicks instead of the usual taps of touch-screens) to play that game.