Adding a pause menu

Now that we have the main menu, we will move on next to building something else that most games will need, a pause menu. In PC games, this will likely be triggered by the Esc key, whereas in a mobile game, it typically needs its very own button. We will make it so that this project supports both.

1. To start off, let's open up the Gameplay scene by going to the Project window and then opening the Assets/Scenes folder and double-clicking on Gameplay, thus saving the MainMenu level if you didn't do so already:

Before we create a button to open our pause menu, let's go ahead and create the pause menu first that we'll be opening.

2. The first thing we'll do is dim our screen when we enter the pause menu. An easy way to do that is having an image scale to cover our entire screen, which is what the Panel object does by default. We can create it by selecting Game Object | UI | Panel. Note that this creates a Canvas and an EventSystem object in addition to the Panel because one doesn...