What is the importance of the "game" that the boys make up to celebrate a successful hunt? How does it change over the course of the novel?

The game is initially simple play. Roger or Robert or another boy simulates the pig and they re-enact the hunt. As the novel progresses, the play acting becomes more violent. At one point Jack suggests they use a "littlun" to carry out a real hunt. Although the boys laugh, Jack is serious. By the end of the novel there is little distinction between "play" and killing.