One of the updates of the Pathologic Kickstarter had something interesting that I think resonates with some of what has been said in this topic. What made me particularly think is the idea that video game don't necessarily have to be fun.
This is completely counter-intuitive, but at the same time, it's the same for all form of art. Not all movies are meant to be fun, and a movie can be very good without being fun at all.
A difference I can see is that games have to be engaging. For a movie, you just need to watch. Stopping the movie requires more effort than watching it through (except for movies that are really difficult to watch, either because they're bad, scary or make you feel bad or uneasy). For the game, you need efforts to keep playing, and it often takes longer.
But I think that the player can be engaged by something else than the promise of fun. The promise of a great story, of a good atmosphere can engage as well. They both did engage me in both the original Pathologic and The Void, no matter how "not-fun" they could feel. But just like an engaging movie might still be difficult to watch, an engaging game can be difficult to play. So in the end, it will still require willpower and effort from the player to play through the game. I don't think that can be avoided.
But if we accept that we can require the player to use this willpower and effort, I guess we can really make different, and very interesting games.