During play of a casino game a hidden bonus feature unknown to the player occurs as no separate indicator is activated. The occurrence of the hidden bonus feature may be at a random statistical frequency or other event. When the player inputs a correct response to the hidden bonus feature, the player receives an additional award. If a correct response is not received or if the hidden bonus feature is ignored, the player does not receive any further award. The hidden bonus feature does not affect the outcome of the play of the casino game.