A couple of lines of code that you need to fix in the book. The book differs from the code you have provided in the source and that makes the game not run properly.
1. On page 150
Vector2 size = Access.ImageSize(element.Image);
should be
Vector2 size = element.Size;
2. For the Access class the screen size in the book is 640x480 it should be 800x480, like in the source
These two cause the ship to stop before it reaches the end of the screen, so just thought I'd let you know.
So far I am up to "Adding the star field" chapter and enjoying this book a lot. Its a great effort by you for which I am grateful. Although I think you need to really have this book proofread a bit more as I found a lot of grammatical and spelling errors. Other than that I think so far this book has been really good.