In order to make it clearer what I was getting at with my previous post, I'll here repeat part of what I said in its comments. The question is: what can roleplaying games do that other forms of art cannot? The answer is: create or change a social relation mediated by images. The example is My Life with Master.
What seems to me unique in roleplaying games, is that they can create a real and new social situation, right there, between you and your fellow players; and they allow you to experiment with this situation. What is so cunning about My Life with Master is that the social relations it creates in the gaming group are an exact mirror of the fictional relations. Observe:
1. The GM needs the players, for without them there is no game and he has no power. The Master needs his minions, for without them he has no power.
2. The GM must bully the players - emotionally and, in fact, almost physically (see the Manifesto on Mastery). He, the actual person, must think up fictional tasks that the players are loathe to play out. And he has the power to make the players carry them out. In the same way, the Master bullies the minions, and makes them carry out tasks they do not wish to carry out.
3. The GM and the players must play on each other's emotions in order to get bonus dice; the Master and the minions do exactly the same.
4. The players are bound to win, eventually, and become the final authors of the story. In the same way, the minions are bound to defeat the Master and have, if not a happy end, at least a fate of their own. (It is not an accident that the game ends with monologues by the players; as the Master dies, so, metaphorically, does the GM.)
What the game has done, then, is create, right there, in the real world, a less severe but still perceptible form of the social relations it is about. It makes it possible for you to not only tell a story about dysfunctional relationships of need and power, it allows you to actually experience them.
No book or movie could possibly do that. Writing can't do that. Improv theater might; but then, that is a kind of roleplaying.
This, my friends, is where the great power of our art lies.