Windows Phone 7 designing is not easy and you need to be a good programmer to program a game in Silverlight.
The Physics Helper Library is a collection of Behaviors and UserControls that make is easier to create 2D physics games in Silverlight using the Farseer Physics Engine. The Physics Helpers have gone through several different iterations – in their original release for Silverlight 2, they were solely UserControls; in Silverlight 3 support for Behaviors was added, and later WPF support was added into the library
Pete Blois (of the Microsoft Blend team), has also ported his Box2D Engine based samples to the Windows Phone and created a really neat physics based game which he demoed at MIX10. If you want to check out the Box2D engine instead of Farseer, you can check out Pete’s work.
The Windows Phone doesn’t have any useful hardware buttons for games, so you can bet that the Accelerometer on the device will be very important for input. Mike Harsh gave a great presentation at MIX where he explained the axes of the Accelerometer:
So if you wish to program anything like a game you should be aware of the classes, namespaces, functions and in short an expertise in a particular language is needed.
The problem is that the emulator included with the Windows Phone developer tools does NOT simulate an accelerometer.
You can see some demos using behaviors here!