A game system comprising a game device used by a first user and a second user, and a controller, the game device including: an association section configured to associate the controller with a user account of the first user using the controller; an image processing section configured to output a video signal for display of either a general screen or a user screen; a first process executing section configured such that while the general screen associated with neither the user account of the first user nor a user account of the second user is being displayed, the first process executing section is configured to execute a process of a general-purpose function in accordance with first operating information acquired from the controller, the general purpose function being a video playing function associated with neither the user account of the first user nor the user account of the second user; and a second process executing section configured such that while the user screen associated with the user account of the first user is being displayed, the second process executing section is configured to execute a process of a first user function in accordance with second operating information acquired from the controller, the first user function being a video game application function associated with the user account of the first user, the controller including: a first operating member configured to be associated with the first operating information; a second operating member configured to be associated with the second operating information; an operation receiving section configured to receive an operation on one of the first and the second operating members; and an operating information outputting section configured to output to the game device one of the first and the second operating information associated with the operation on the corresponding one of the first and the second operating members; and wherein: while the user screen is being displayed, the second process executing section is configured to execute the process of the first user function in accordance with only the second operating information acquired from the controller. an association section configured to associate the controller with a user account of the first user using the controller; an image processing section configured to output a video signal for display of either a general screen or a user screen; a first process executing section configured such that while the general screen associated with neither the user account of the first user nor a user account of the second user is being displayed, the first process executing section is configured to execute a process of a general-purpose function in accordance with first operating information acquired from the controller, the general purpose function being a video playing function associated with neither the user account of the first user nor the user account of the second user; and a second process executing section configured such that while the user screen associated with the user account of the first user is being displayed, the second process executing section is configured to execute a process of a first user function in accordance with second operating information acquired from the controller, the first user function being a video game application function associated with the user account of the first user, a first operating member configured to be associated with the first operating information; a second operating member configured to be associated with the second operating information; an operation receiving section configured to receive an operation on one of the first and the second operating members; and an operating information outputting section configured to output to the game device one of the first and the second operating information associated with the operation on the corresponding one of the first and the second operating members; and wherein: while the user screen is being displayed, the second process executing section is configured to execute the process of the first user function in accordance with only the second operating information acquired from the controller.