The preset invention provides a game system wherein data is prepared for each stage to execute plural stages separately. When a user has made a predetermined result in one stage, the user progresses to the next stage. The game executes each stage in a predetermined sequence. When a predetermined condition for ability improvement is satisfied, a parameter specifying the ability of a game character is increased. The game allows the user to select one stage from the plural stages out of the predetermined sequence, and the selected stage is executed with the parameter specifying the character ability set to a value below that which would be expected for the selected stage, for example, an initial value for a first stage.