How to do it...

To create the simple 2D Space Girl mini-game, follow these steps:

1. Create a new, empty 2D project.
2. Import the supplied Sprites folder into your project.

3. Since it's a 2D project, each sprite image should be of the Sprite (2D and UI) type. Check this by selecting the sprite in the Project panel; then, in the Inspector panel, check the Texture Type property. If you need to change its type, you can change it from the drop-down menu and then click the Apply button.
4. Set the Unity Player's screen size to 800 x 600 by choosing it from the drop-down menu on the Game panel. If 800 x 600 isn't an offered resolution, then click the plus (+) button and create this as a new resolution for the panel.

5. Display the Tags and Layers properties for the current Unity project. Choose menu and go to Edit | Project Settings | Tags and Layers. Alternatively, if you are already editing a GameObject, then you can select the...