I played this game for a change, and it was surprisingly good. You can make entire solar systems with moons, if you time things carefully. Here is a mini-planetary system where one planets orbits a star, and it has three permanent moons. Each moon has a different orbit speed/ orbit radius making it even more interesting.
Here's the thing that annoys me the most about this game.
After two planets collide, the amount of mass in an area suddenly decreases. It's really annoying, as it means my carefully planned system just flies apart whenever there is a collision. This is mainly annoying when I'm playing with chaos -- "ternary planet system."
But yeah, this is an awesome game. You might notice that I've used to post a lot about this game.