1. A method of generating a companion experience on a companion device, the method comprising: receiving, on a companion device, state information describing a video game being output for display by a primary device, wherein the state information identifies the video game and a game level for the video game; identifying, by the companion device, one or more companion applications that provide a companion experience related to the game level within the video game; and outputting, on the companion device, for display on the companion device, which is separate from the primary device, a selection interface that allows a user to select a companion application from the one or more companion applications.