story line only, but if that's what I cared about most I'd watch GTA the movie or something. It's a video game and I want to play and buy stuff. The only reason you have to even do missions is to see what happens in the story. I mean it's practically the same thing every time...go to a location kill a bunch of people, run from the cops. For this to be advertised as such a living and breathing and realistic world, you're really limited.
