Fun is a hard concept to pin down, especially in video games. We have some ideas about what’s fun and what isn’t (sewer levels), but as always the details are important. A major detail comes in the shape of player expectations, that is, what they think about your game and what your game is really about. Managing expectations in the game can be a source of fun, combining surprise, safety, and just a little bit of frustration to overcome. Check out this article on the subject of player expectations. Gamasutra has the story.