Yes. By backing or preordering the game you get the OST as a gift and a sale price of $5. Game price will be higher upon release. So hurry up!
You get all available: Win, Mac, Linux, OUYA, Desura and Steam (if greenlit)
Yes. You will get early alpha access and future updates of the game, you won't have to pay additional fees.
Yes, will be updated at least once a week at
Yes! As soon as the minimu goal is reached you will be able to paypal at: http://ansimuz.com/site/kickstarter-pledges-via-paypal/
Don't see the answer to your question? Ask the project creator directly.