Cool game, definitely reminds me of spore with the whole evolution thing. I really liked the references to real life prehistoric creatures like the nautilus and the creature that scientist couldn't tell which was it's head and which was it's tail (i forgot it's name).
But i didn't really like how when you are at the edge of the map an enemy can just spawn on top of you and instantly kill you, maybe you could have an indicator there before the enemies spawn.
Also maybe could have added more objects in the background so you could tell if you were actually moving or not.
Good job!