Epic of Gilgamesh

Epic of Gilgamesh is almost like the story of Noah where there is a flood and a main hero (Noah/Gilgamesh).
These two stories however differ in many ways. While the story of Noah is from the bible thus teaching about the power of God and calling people to believe in God, Gilgamesh on the other hand is an epic - a mere story for fun - and it is not calling anyone to believe in any God. Another difference is that in the bible, the main reason for the flood is given as due to the sins of man from the generations of Adam and Eve but in Gilgamesh, it doesn't say explicitly the reason for the flood. Utanapishtim just tells Gilgamesh to build a boat.
These and many more can be seen as the differences between these two stories