A Work of Art
And little more. As many have said game play is rather poor but this "game" isn't about play mechanics or even being a platformer. It's simply a beautiful expression of a dark and alluring story of god and his fallen bride.
As many have said they don't understand the story, here is what *I* interpreted it to be:
[SPOILERS]
You play as god who created man as a perfect gift to his wife, mother earth [or simply the Goddess of Nature as I believe the game refers to her]. However, Earth Goddess soon tires of man's weakness and decides to kill them, infecting the earth with horrible disasters. God, filled with sorrow at his lost children, kills his wife and abandons earth.
The game begins at Earth's end, and God has decided to come back in mortal form to find his lost love. Along the way you meet the frightened mortals cowering on a damned planet who are twisted into evil creation by the Goddess. One such mortal, [the first boss] finds the Goddess' heart and in turn becomes a God himself. He says that he was waiting for God to come back and face the children he abandoned. Upon his death he states that he only regrets God not coming back for man, but only his wife. [There can be some assumption that the wife's heart corrupted the man into an evil being, but that's all speculation]. As you progress further the goddess becomes more and more enraged turning man into more and more hideous creations. You also find strange Anubis masks that were really explained [that rip off your head and give you a weapon]. Possibly this is a way for God to access his powers or simply a metaphor for "God's Wrath". Regardless, using this "power-up" You eventually make it to the center of the Earth, where the Goddess resides. After beating her she seems to accept that she was wrong yet seems indifferent whether or not she's forgiven. It is likely that the two deities become one once again although this is also mere speculation.
*Note this is merely my interpretation and I could be entirely wrong*