A gaming machine provides an operation unit, a display unit, and a controller. The operation unit receives an operation of the player. The display unit displays a primary game and a feature. The controller establishes an outcome of the primary game and establishes a primary game award. The controller establishes a base feature award as a function of the primary game award, sets a feature trigger award equal to a multiple of the base feature award and provides the game feature to the player in response to detecting a trigger condition. The game feature includes a number of free plays. For each free play, the controller establishes an outcome of the free play, detects a second trigger condition and responsively awards the feature trigger award to the player and sets the feature trigger award to another multiple of the base feature award.