Various embodiments are directed towards employing one or more physical sensors arranged on or in proximity to a video game player to obtain biofeedback measures that are then useable to dynamically modify a state of play of a video game. The sensors may be connected or even unconnected to the game player, replace, or otherwise augment traditional physical game controllers. The sensors gather various biofeedback measures and provide such measures to a biofeedback application programming interface (API). Before and/or during video game play, the video game queries the biofeedback API to request inferences about the game player's state of arousal. The response to the query is then used to modify the state of the video game play. Where the video game is a multi-player video game, biofeedback measures from other game players may also be obtained and used to further modify the state of the video game play.