There needs to be just a little bit of crazy when dreaming up a new concept.
Well, we look for sources of inspiration in pop culture in general. It's very important for us that, when it comes to storytelling, we don't look into other video games. We'd rather look into other mediums - movies, television series and books - for sources of inspiration.
Prose is an art form, movies and acting in general are art forms, so is music, painting, graphics, sculpture, and so on. Some might even consider classic games like chess to be an art form. Video games use elements of all of these to create something new. Why wouldn't video games be an art form?
I think that in general - well, at least it's true for me - you tend to put something of yourself into the story as a whole. Not necessarily in any character, you understand. But you've got your own way of looking at the world, and that naturally will affect how you craft a story.
It's also very important to make sure that the main character and the player are completely in synch.
The way you write dialogue is the same whether you're writing for movies or TV or games. We use movie scriptwriting software to write the screenplays for our games, but naturally we have things in the script that you would never have in a movie script -- different branches and optional dialogue, for example. But still, when it comes to storytelling and dialogue, they are very much the same.