I think it would be really fun, as a cool next version feature of your game, to allow player's slingshot projectiles to bend to the asteroids' gravity wells, thus enabling the player to use one smaller asteroid as a ricocheting unit to hit a larger unit that's obscured by several other units, say, and in doing so, smash a whole bunch of smaller stellar rocks (maybe including the one you ricocheted around) in one fell swoop. That would be really cool. Please consider adding this feature, if it isn't already in there. (I couldn't tell if it was, based on your blurb above.)