Last year I set myself a challenge to see if I could write a game in Unity, and sell it. So I decided to write a small sliding puzzle game called Muddle Puzzle. I used the professional version of Unity 5.3.x, Visual Studio 2015 Community Edition and C#. It was an interesting experience, and now the game is released on itch.io. The URL to buy the game is: http://yewtree.itch.io/muddle-puzzle. You can view the video below to see the Muddle Puzzle gameply.
XNA 4.0 Game Development By Example authored by Kurt Jaegers is an excellent book for anyone who wants to learn XNA 4.0 games development. As you work through the book you develop some games including Flood Control, Astroid Belt Assault, Robot Rampage, and Gemstone Hunter.
This book comes in two versions one for Visual Basic .NET programmers, and the other for C# programmers. The good thing about this book is that it is very easy to read, and the examples are easy to follow. For anyone new to games programming this is a good place to start