I have always been attracted by the
method for creating Ico that Fumito Ueda called "Subtracting Design". The idea is that you remove everything non-essential from your game and put all your energy in the few remaining elements.
But now I'm starting to think that such a "negative" approach is just a remnant from the age of when videogames were games. When you think of videogames as
games, you get all sorts of ideas for gameplay and features and rewards and levels. Then, confronted with the reality of production, you need to start cutting and cutting until you have a concept that can actually be released. In my experience this cutting continues throughout the production process, as things take more time than estimated and schedules slip. It's heart breaking to have to cut features just because you need to release on a certain date, or even release at all.
I think notgames is starting to point in a direction of a new approach. An approach that one could simply and optimistically call
additive design. Since we're not making games, we could start any project with the simplest of concepts. Just a basic situation, a virtual world, a piece of text rendered in a certain way, a single image, etc. It could be anything. And that thing, since it doesn't need to be a game, can be the finished product. Simple, straightforward, no cutting.
Of course, once you're in the process of producing this simple concept, you will get new ideas for additional features. And you can then decide to add them or not, based on whatever norms you have for such decisions. The point being that such additions do not jeopardize the release of the product, or even the quality of the concept. They are additional features, decorations, extra. Fun to have but not essential.
I think some of us are better at having the simple ideas required to apply additive design. I myself have a lot of trouble with coming up with simple ideas. Or at least with accepting that a simple idea can be a good enough starting point. My mind always starts wandering, inventing things to do, places to see and then inevitably I need to start cutting again. So for me, it takes discipline.
But I think for others, and more now that videogames don't need to be strictly games anymore, this will be much more natural.