How would you describe the game to someone who's not a hardcore FPS fan, why is it going to rock their world and have them running to upgrade their office PC to play it?
We've shown Half-Life 2 to a number of very casual or "so casual they don't" gamers. The characters and the world interactivity seems to be the key for them. Usually they tell us "it looks just like a movie, except I'll be in it", and we grit our teeth and say "Interactive Movie" is a Really Bad Thing, and they are not to say it again, or we'll take away their Half-Life 2 hat.