Armando Marini @ Gamasutra: "Let's face it, our industry is a complex one. There is no shortage of theories on what makes a game a success or a failure. The fact of the matter is that all the theories are valid to some extent but none of them are a silver bullet. This entry will not be either.
What I can do is help you to understand this medium that we are working with. I'm going to put forth two notions that can encompass what it is we do and within these ideas, all is possible. These two notions are the cost/benefit analysis and a philosophical argument known as the sorities paradox.
When Metal Gear Solid 4 was released, there was some furor over the lengthy story sequences. The complaint was that there was not enough "game" in it and too much passive viewing of the story. This is a complex example because there is a great number of little cost benefit analyses for the user. It also clearly resides somewhere in the middle of the Sorites paradox. Some may not feel enough "grains" exist in its "heap" of interactivity and therefore they felt unsatisfied. Many though felt it had a very good mix of elements. I for one enjoyed it tremendously."