The techniques in this book were not invented by me so you are completely free to use any/all code from this book in your own games free or commercial. I also have no problem with you using any of the assets (graphics and sound) in your own games free or commercial.
The only restriction is that you can't publish the code itself or otherwise make it available especially in tutorial form as this would likely bring you into copyright problems with the publisher as well as devalue the many months I spent putting this work together.
If you have been helped, inspired or used my assets I would be grateful for a credit, but it is not required.