I've put online an article entitled "Emotion Engineering in Videogames, Toward a Scientific Approach to Understanding the Appeal of Videogames".

It's a theory about how to design game systems that can induce a chosen emotion in a player and, in fine, about how to find a certain type of abstract game design rules that are applicable to all videogames, across all genres. This is a more detailed model than the one I presented at Game Focus Germany 2008.

Here's, for instance, one way to induce hope in a player using only gameplay systems:


The article explains what this all means. Hopefully.