Abstract
In multiplayer gameplay, communication occurs among players. This has been exploited in game design, where games are used as a communication tool. We investigated the occurrence and changes in player communication during games. The research was conducted in an implemented cooperative game, and we observed changes in communication by making rule changes to the initial prototype. At the result, the communication became more active with the inclusion of a rule proposing consultation. And by consulting before playing, the rules were better understood, and the game flowed better. In addition, winning as expected gave a sense of achievement and they became less attached to the game.