Lots of cool philosophical articles and concepts. The formatting was really terrible in the center of the book for Kindle, furthermore near the end the book started to lose steam and incorporated less structured forms of games, such as improv. Some of the articles did not tie fully into the theme of the book, however no article detracted from the book to a degree where it diminished the usefulness of the book. Also I looked up a few of the major concepts mentioned as being part of this book, GNS Theory has fallen out of favor with its creator. However if you are interested at a look at the major qualities and though processes that go into developing and playing tabletop games, this book gives a great framework (not entirely complete, there are $10 kindle books for that) for thinking through strategic choices that are presented in games.
However the knowledge in this book can be readily replaced with some knowledge of Wittgenstein, Immauel Kant, and a few book from other authors.