Yeah it's a true detective game. And, it's not one of those corny games where the clues are obvious, with some glowing item lying around. You have to really look around and ask questions. And drive from location to location looking & asking. Reading facial expressions is key too.
All the characters in the game that you talk to are done by real actors, facial expressions & movement. So there will be no lip-syncing problems. Pretty much like Avatar. I think this will change the way games are made, because it's cheaper to have an actor do a performance, than it is to have an actor read the lines, then pay animators to make the animation look real, and try to sync the mouths with the words.
It's also going to be the biggest city Rockstar ever did. They re-created the L.A. area in the 40's from Downtown to Hollywood.