There was a lot covered in this chapter on animation. Animation is probably the most important part of game development, as without it nothing on the screen will move or change. You learned how to add assets into the SpriteBuilder so that your games will look much more polished. You then learned how to animate these assets. Of course, sometimes, SpriteBuilder can't meet all your needs; so, you also learnt how to perform animations in code.
In the next chapter, you will learn how to put together user interfaces. You will also learn about the different ways of accepting user input through touch and the accelerometer.