This is a question that popped into my mind today, and I think I've got the answer. A game does not become mature when it subtracts out a bunch of stupid violence and replaces it with stuff about the human condition and emotions and thoughts and stuff, and vice versa. I think a game truly becomes "Mature" when it becomes the best at what it is meant to do. When an action game does action perfectly, it is mature. When a heavily story based game that touts non-linearity actually does that well and it feels like you're not being lead along by the nose, then it's mature. Maturity doesn't mean hunkering down and getting a dead end accountancy job, knowing the best years of your life are behind you. Maturity means, at least in my mind, picking a lifestyle then perfecting the lifestyle, making it the best lifestyle or best life possible. That is what I think makes a game, and indeed a person, mature.
So what about you? What makes a game mature to you?
So what about you? What makes a game mature to you?