1. A game device comprising: a signature memory unit which stores a trace of a signature pattern associated with each of a plurality of players; a status memory unit which stores a game progress status for each of the plurality of players; an input receiving unit which receives an inputting of a trace from an arbitrary player; a restarting unit which stores a current game progress status in the status memory unit in association with a current player when the received trace is similar to one of the stored traces and the current player is different from the arbitrary player associated with the one of the stored traces, and which restarts the game from the game progress status stored in the status memory unit in association with the player associated with the one of the stored traces; an advancing unit which advances the game based on the received trace when the received trace is not similar to any of the stored traces and the received trace is similar to a predetermined instruction pattern; and, an adding unit which stores the received trace in the signature memory unit in association with a new player having a game progress status not stored in the status memory unit, and which stores the game progress status at the beginning thereof in the status memory unit in association with the new player, thereby adding the new player, when the received trace is not similar to any of the stored traces and the received trace is not similar to any of the predetermined instruction patterns.