Originally the first installment was supposed to be rather short, but I felt it wouldn't be enough.  Though it was primarily just an introduction to the world but wanted players to get a better feel for the kind of game and story I was creating so I introduced Free Mode as a means for the player to be able to create their own character and freely interact with the world.  Then I saw the opportunity to add short side stories that add more insight to the main story.  This way it would fix my issue of the game being too short but then I added additional story to the main story which originally only had 4 chapters to it.  Ultimately, the process is to set the game up to write tons of stories in this massive world which will only create more gameplay as I come out with more games/stories.