Summary: Quite nice game. Very short and after a while there isn't much to do but you can kill time with this one amazingly easy. Just fly around as hunk of rock. There is always room for getting achievements done too if you are that type of the person. Just don't expect any revolution.
Summary: Decent game but it's not entirely apparent what they want you to do. Sure you float around and that's pretty neat but all the missions in the game are very vague with how to go complete them. Floating around is fun for awhile but it gets boring pretty quickly.
Summary: The concept seems fine - you start as a rock, grow and become a planet, later star. Finally you "own" other planets and develop a star system etc. Throw in an atmospheric music and some task or missions to perform in-game... and it should work. Sadly, it's not.
Summary: As others have mentioned, this is a VERY short game with very little variation. Is it fun? Yes, for a while. After that, you feel that you've done it all before. There are different "missions" that you can try to accomplish, but they're your basic Fedex variety quest.