When you read through Genesis 1-3, it doesn't appear that the text presents us with a cosmic battle of good verses evil. It appears that Good and Evil — the fruits from the tree similarly named — are inside of us, and that the "bad guy" in the story is merely one who whispers and makes us feel ashamed. But the whispering one is ultimately cursed and doomed to die by having its head crushed.
Perhaps this makes the little cartoons of the devil-and-angel on your shoulder (as versions of yourself) a good metaphor of our day-to-day lives.