What we want to show with GAR is that games can produce their own content, and that evolution (i.e. genetic algorithms) is the natural choice for making that possible. Think about it: Players naturally spend more time with content that they like than with content that they do not like. Therefore, the fitness function is simple: How much does each piece of content get used? In GAR, that question translates to how much each weapon is used. The most popular weapons become parents of new mutant weapons that are spawned in the universe to be discovered in the future. That way, new content is an elaboration of the old content that people liked. With multiple simultaneous players, the process is enhanced by all the feedback coming from multiple users. The cool thing is that nobody knows what weapons will be like in the future, but whatever they are like, they will be derived from weapons people enjoyed in the past.