I think those sections of Sunshine are undoubtedly the inspiration for Galaxy. Like the toy galaxy, it isn't even set in space - it's set in a kids bedroom. Yet it still has all the gravitatinal, planetary effects. Think theres at least one other which does the same, in the atmosphere of a planet but still the attributes of being in space. Doesn't really fit in with the rest of the game, but no complaints.
Speaking of complaints, I have discovered one thing I don't like about this game. Those bloody trash destroying minigames. So pointless, takes like 10 attempts to do it and gets me completely fed up.