I created the last of 3 games for the DVLUP.com competition, another space game where you have to launch the Saturn V rocket (Apollo) to space, and orbit around the earth.
I wrote the physics and math myself, ignoring the ones that comes with Unity. It was a fun project, but took more time than estimated. 
Anyways, here it is – it’s very hard and not for those who wants intense action.
Modern art using the GPU 
I am a beginner with Windows Phone programming at the Moment, and i have made my dev licence to work with store apps too. I have not tested how to develop for Windows store, but i read you are using unity. What does the licence cost for it?