13. Angry Birds
Apparently Angry Birds began with a piece of concept art, just a picture of the birds rumbling along the ground looking pissed. The image was so engaging Rovio designed the game around it (with liberal inspiration from Crush the Castle), and you can see why. The birds were cute enough to appeal to everyone, furious enough to be ideal video game protagonists, and merchandisable enough to make them very rich indeed.
Iconic moment: A bird hurtles through the air, slaps up against a thick wall and rolls to a stop. You adjust the trajectory and fire again. The outcome is exactly the same. Now who's angry?