One more to add:

The plot in Darkspore sounds very grandiose and involves an experiment by an ancient race of omnipotent beings known as the “Crogenitors,” who created all living DNA in the universe but experimented with a new “exponential DNA” that was unusually powerful but highly unstable. It seems that one ambitious member of this mysterious group not only fused the unstable DNA with his own, increasing his own power substantially, but also created an army of monsters powered by this new genetic material that destroyed most of the other Crogenitors, leaving the last few survivors to flee to deep space with a squadron of heroes stuck in a cryogenic slumber until a solution to the problem could be deduced by the powerful computers of those last remaining DNA architects.

As the game begins, the solution to the exponential DNA invasion has been found: You. You awaken from your sleep as a genetically enhanced hero with the power to oppose the invasion head-on, and fortunately, you won’t be alone. Rather than force you to focus on developing a single character that belongs to a single character class with a limited skillset, Darkspore will actually let you select a team of three different hero creatures to take into battle and will also let you gather a huge collection of alternate heroes for you to use and develop as you see fit.

full preview at GameSpot