You should play all the routs ! All of them are great, and worth the ride. And, to get the second CG with Lars. You have to play his Episode (The one in the bottom left of the tittle screen)
I would recommend you to read all the routes plus their episodes. All of these will help you to understand more about whats going on with Walter's past and some other stuff. It's a really fun experience with how they added the one-time-event on Lars' and Anders' route.
