sentence: "There's nothing like sneaking up, and taking down a guy, and getting that notice that you have the Master Ninja trophy. It means you have improved, you are continuing to master the game, and we are recognizing that. It's not just 'Oh, here's another guy to kill.' It's 'Here's a guy who matters in a larger context. And when I defeat him, that will be recognized.' It's a solid way of rewarding and reinforcing a game's action."