A slot game tracks a number of special symbols through multiple spins and unlocks game windows and/or stacks of sticky wild symbols based on the number of tracked special symbols meeting or exceeding a threshold value. Each stack of sticky wild symbols replaces a given reel for the remainder of the game or instance, such that that reel will no longer receive a random outcome and can no longer land special symbols as display symbols. As more special symbols are accumulated, more game windows will be unlocked and more stacks of sticky wild symbols will be placed on the game windows.