Blarg, forgot about english. (well, humans sort of come with english though, I'd say)
"Humans: All-Inclusive"
But generally everything in the sense of "stars, gravity,etc" is taken for given in the world of about everything ever, so I felt that was a given. (I mean, have you ever read a book in which there aren't planet(s), stars, space (even if the character doesn't go there), gravity, mortality (except the bible on this last one, apparently

)?)
And the zerg are based off a weird larva (called a Zerg) adapted by really weird aliens to take over other beings. Not particulairily world-like, really ><. They may manipulate DNA, but there's alot more weird stuff than that.
Protoss... that's what I'm talking about with magic and such ;p