If you know your way around Unity, the book will probably teach you a couple of very specific advanced techniques; just don't expect to gain much general knowledge about 2D and 3D graphics, AI and shaders, or you'll be disappointed.
I can sincerely recommend the book to anyone, trying to get a glimpse into the world of game development. It can really only serve as the first step on the path to becoming a game developer, but it's definitely enough to see if that's something for you and worth exploring further.
BallMaster is a puzzle game with a simple basic idea and (hopefully) addictive gameplay. It is based on an old game named Logical. This game tries to bring its idea to newer Amiga hardware and also tries to extend the original game with some new ideas.
I have designed over 100 levels for Emerald Mines - a quality Amiga port of 8-bit gaming hit Boulderdash. You can download them for free. If you don't have an Amiga, you can use an Amiga emulator instead.