I'm not a fan of the license chosen for the source code. It's just going to intimidate people from using any example code for their game no matter how different it is.
If I want to use any example class from the code in a commercial project I'm technically not allowed. Technically this book is teaching me to create things I'm not even allowed to sell. This is disappointing to me as I've worked on a project very different game logic wise to the book (while still using lots of code from the book) for months and I've only just now learned of the license.
Please consider changing the license.