A game system reduces a compensation parameter by a consumption amount set for a game medium and sets the medium to be useable, increases the parameter to up to an upper limit of a predetermined value when a predetermined increase condition is satisfied, stores a normal game medium in which the set consumption amount is equal to or less than the value, and a special game medium in which the set consumption amount is more than the value in a storage unit as the medium in association with a player, reduces the parameter by a given reduction amount and increases an accumulated parameter in accordance with the reduction amount, and sets the special medium to be useable by reducing the compensation and/or accumulated parameters so that a sum of reduction amounts of the compensation and accumulated parameters together is equal to the consumption amount set for the special medium.