This book contains a nice list of building blocks of games, but unfortunately it doesn't list them anywhere. It would have been nice to have a checklist to follow instead of having to page through Level Nine (chapters are called levels). Examples of building blocks from Level Nine include: targets, competition, chance, time pressure, scarcity, puzzles, novelty, levels, currency, progress, forced decision, points, and more.
I picked up some useful ideas and reinforced some earlier thoughts I already had about games, apps, and life. Overall, worth a quick read and I will return to it later to see if I can pick up more ideas. I find that I pick up different ideas from a book depending on when I read it -- some books were great when I was a teenager, but now would bore me -- and visa-versa too!
In app design and programming the basic books were interesting at first, but now I don't need those any more. I'm looking for both more detail and more high level discussion of concepts and ideas.