The rule is that war is a given in video games. The second game ever made had the word right in its name. MIT's Model Railroad Club made Spacewar! to indulge their predilection for Sci-Fi pulp first and foremost, but that game nonetheless fired the medium's first weapons, and saw the first players trying to gun each other down in combat. Those guns have never left games, and they have arguably done more to define the art of making games than anything else. Video games have been more defined by humanity's compulsion towards armed conflict than any other cultural force.