The sky's the limit, and Unity starts us off with an endless sky. But, through this chapter, we've seen that that endless sky can actually trap us into an ambitious concept that we'll have no chance of completing. So, let's redefine the sky. Instead of wondering how big and complex your game can be, think about the endless array of simple interactions and moments of joy our world contains. Throwing and catching a ball, knocking a pile of stuff over, feeding an animal, growing a plant the world is packed with simple, effective interactions that ignite our most primitive, most basic Joy Cortexes, which is a neurological term that I've entirely invented just now.

If you want to discover one of these joy-producing real-world moments, study a child. Because games are all about play, the simple things that amuse and delight children and babies are the stuff of award-winning games. What is Metal Gear Solid if not a complex game of hide and seek? Rock Band and Guitar Hero are digital versions of all those times you played air guitar and pretended to be a rock star in front of the mirror with your bedroom door closed. Have you ever rolled snow into giant balls to build a snowman? Katamari Damacy is the video game expression of that joy-producing activity.