actually if you look at most games the only difference between the game portraying the story and a movie is that in the game there is usually a need to have conflict appear once every... 5-10 minutes so that the gamer remains entranced, and the fact that instead of watching the character make his way through the story, you lead the character through it.
An example would be Sam and Max, you never actually were able to progress beyond a certain point without doing something, so that whole scene was you just watching and reediting the proverbial film in a way that you choose, Halflife is even better because for the most part, barring a cheat you MUST go in ONE way and down ONE path at ONE time, Admittedly the watching a guy in the corner of the screen who's barely in the shot do all the talking is gone and instead you can either look at the guy or do something else while the script runs it's course.
Another quick thing, if the difference between a game and a movie is that a director controls what you see rather than the viewer/player, then why are books considered art? after all, all an author does is describe the situation and location and have you fill in the gaps as a reader. which is essentially what you do as a gamer in a game.