Dear Rockstar,   I'm a grandfather who has been playing video games since Asteroid and Pac Man. I spent an obscene amount of time playing GTA 3 and, at the time, fully expected to continue being a Rockstar customer, gamer and fan. GTA IV, however, began to turn me off. There were too many situations in which the challenge was based on overcoming the limitations of the game engine and control interface in order to tell my avatar what to do. This is bad design, guys. Challenges based on