1. A non-transitory computer readable storage medium comprising game program instructions, the game program instructions, when executed by a processing system, causing the processing system to: acquire a first user image captured by a camera before starting a game processing; generate user feature data indicating a feature of a user based on the first user image; store the user feature data; acquire a second user image captured by the camera after starting the game processing; determine whether or not the second user image includes the feature of the user by comparing the second user image with the stored user feature data; and execute the game processing based on the second user image when the second user image includes the feature of the user, execution of the game processing including, at least, determining whether a game clearing condition is satisfied based on the second user image, the second user image being obtained repeatedly during execution of the game processing.