AusGamers recently posted a feature talking about the maturity of game design in the industry, and cites Tomb Raider, Far Cry 3 and The Last of Us as games leading an adult-oriented charge when it comes to creating games with a greater sense of reflective morality on the player.
From the feature:
"What I’m exploring here is more in line with an adult look at what it means to drive an avatar through an experience, but to finally have that experience reflected upon the player from a point of morality. Be it through player-choice in how you tackle a potentially dangerous situation, what it means to actually take a life or, further than that, what it would mean to take multiple lives if you were thrust into an uncontrollable situation. From the growth in maturity I’ve witnessed, games are quickly becoming less about forward motion, and more about consequence..."