provided sufficient credit to commence playing the mechanism 24 may instead of the coin input chute 24 1 or the bill collector 24 2 or in addition thereto be a credit card reader not shown or any other type of validation device finally the controller 36 drives a payout mechanism 40 which for example may be a coin hopper for feeding coins to the coin tray 30 to make a pay out to a player when the player wishes to redeem his or her credit the game 16 played on the gaming machine 10 is a spinning reel game having five reels 18 further the game 16 includes a bonus feature where upon the occurrence of a predetermined trigger condition in a base game of the game 16 a series of free games is awarded the bonus feature includes an indicator as will be described in greater detail below which clearly indicates to a player that the potential return to player percentage in the bonus feature is higher than that which is applicable in respect of the base game of the game 16 in the description which follows it is assumed that wins both in the base game and in the free games of the bonus feature pay from left to right for the game 16 described in this example it is assumed that the set of symbols applicable to the reel strips is as follows diamond substitute sym_a sym_b sym_c a k q 10 9 s scatter the diamond symbol 58 fig4 is a substitute symbol which substitutes for all other symbols apart from scatters in making up winning combinations for each symbol apart from the diamond symbol 58 there will be a paytable of prizes that applies for certain winning combinations for example 5 sym_a.