A game system includes a game progresser, a storage, a game reproducer, and a changer. The game progresser is configured to control game progress in accordance with a player's instruction information. The storage is configured to store a game-play-history of a first-player in accordance with a first instruction information of the first-player. The game reproducer is configured to reproduce a first game progress of the first player based on the game-play-history, during a second game progress progressed by the game progresser in accordance with a second instruction information of a second-player. The changer is configured to change at least one of: control on the first game progress of the first-player reproduced by the game reproducer; and control on the second game progress of the second-player to be progressed in accordance with the second instruction information, with reference to at least one of first and second player's game situations.