Update README, add banner image

README.md

@@ -1,9 +1,21 @@
-# Squash the Creeps
+# Your First 3D Game: Squash the creeps 3D
 
-Squash the Creeps is a free and open-source game demo for the Your first 3D game tutorial in the official Godot documentation.
+![Squash the creeps banner](images/3d-game-banner.png)
+
+Squash the Creeps 3D is a free and open-source game demo for the [Your First 3D Game](https://docs.godotengine.org/en/latest/getting_started/first_3d_game/) tutorial in the official Godot documentation.
+
+The tutorial series is completely free, open-source, and teaches you to create a 3D game from scratch where you avoid and jump on alien creatures.
 
 ![squash-creeps](https://user-images.githubusercontent.com/12694995/99914544-b2815f80-2cc3-11eb-9fc3-46b61d2083f5.png)
 
+It covers:
+
+1. Handling player input.
+1. Moving and jumping in a 3D game.
+1. Spawning enemies randomly around the game arena.
+1. Using the built-in animation editor to breathe life to your game
+1. Creating a complete game loop with lose conditions, score, and the ability to restart.
+
 ## Credits
 
 `art/House In a Forest Loop.ogg` Copyright © 2012 [HorrorPen](https://opengameart.org/users/horrorpen), [CC-BY 3.0: Attribution](http://creativecommons.org/licenses/by/3.0/). Source: https://opengameart.org/content/loop-house-in-a-forest