Understanding physics is a nice way to start appreciating the natural world around us. Once you start observing and imitating your surroundings, your games will be more organic and believable. This is why I introduced vector and scalars values to you. One of the first scalar values that you already knew about was speed. You've been using the vector value velocity all this time, but now you understand it more in depth. Acceleration is the change in velocity, and you experienced some cool demos while learning all about it. You then touched upon gravity without getting into the highly complicated math that can go behind it. Then wind was introduced in a way that you were able to better understand it as a vector entity. And finally, you learned about friction, the force that opposes all other forcesthis was also coupled with a cool demo.