Players can now actually lose!

If any asteroid crashes on your planet, it will spin out and force you to restart from the beginning. There is no actual level progression yet, so this really doesn't change much, but at least the system is in place. 

I'm pretty happy with the idea of having all asteroids crash into the earth when you lose. I feel like it's a good use of my orbiting system, and messages very well that you failed humanity.

Next step : Implementing some kind of difficulty progression as you beat levels.