Genesis 1 and Theogony both detailed the creation of the universe according to the religions of the Hebrews and the ancient Greeks. In Genesis 1, the earth and the heavens were created out of nothing by one God. This God also created plants and animals to fill the earth. God had the unique qualities of being omnipotent, sovereign, and good. Theogony had a much different story for the creation of the universe.
In Theogony, the Earth and the Heavens were gods which sprung from chaos (it is not clear if chaos was some sort of god). Earth and the Heavens propagated yet more gods, of which some were material things, such as the Sun and the Moon, and others were immaterial things, such as Strife, Friendship, and Deceit. None of these gods were omnipotent, sovereign, or good.
Genesis 1 centers around the creation of the world by the hand of one almighty deity. In Theogony, creation is the result of the procreation of many deities.