Principles of Game Design
There’s been a lot of bulleted lists lately for some reason. I don’t particularly like the format since it promotes a writing along the lines of presenting a set of loosely related concepts as having the same (usually high) truth value, rather than presenting each issue separately and arguing several views on it.
I did like EA veteran Matt Allmer’s piece The 13 Basic Principles of Game Design, though. Inspired by the Nine Old Men’s principles of animation, Allmer proposes a set of recommendations to keep in mind while designing, while some are obvious and others nowhere near universal, all of them are sound.