Create a new scene and name it Main Menu. Next, drag the Audio_Config, Video_Config, and Config_GUI scripts to the main camera. These will be used for our Options menu. Next, create a new C# script, name it MainMenu, and add this code to it:

void OnGUI()
{
  if(GetComponent<Config_GUI>().optionsGUI == false)
  {
    if(GUI.Button(new Rect(700, 400, 150, 50), "Play Game"))
      Application.LoadLevel("Chapter 10_a");
    if(GUI.Button(new Rect(700, 475, 150, 50), "Options"))
      GetComponent<Config_GUI>().optionsGUI = true;
    if(GUI.Button(new Rect(700, 550, 150, 50), "Quit Game"))
      Application.Quit();
  }
    
  GetComponent<Config_GUI>().OnGUI();
}

For this script, all that you will need is the OnGUI function. This code will create a few buttons that will be used to either play the game, show the options menu, or exit the game. Save this script and drag it to the main camera as well. When you run the scene, you should be able to see buttons similar to the ones shown in the following screenshot:

We will create the level that we will play in. We will start off with creating just one level; once we start playtesting, we will clone the scene to make them. To make this simple, I'm using the scene from Chapter 5, Enemy and Friendly AIs and naming it Chapter 10_a. Doing this will give us a playable environment, as well as an enemy. Now, delete the main camera that is in the scene and drop in First Person Controller.

If you run the scene, you will see that the skeleton is tiny! This is because of its scale when it is imported to the engine. In the SkeletonData folder, click on the skeleton model. You will see the Inspector window open with the imported model data. In the Scale Factor property, change its value to 0.0225; this should make the skeleton look bigger. This value is the one that I am using, but feel free to use any value that looks good to you and fits the scene.

Now we need to make a few GameObjects and prefabs. First, we will create a gun for our player. Drop a cube primitive and scale it into a skinny rectangle. Move it up to the camera and place it where a gun typically is in an FPS. In the Hierarchy window, drag the Gun object and drop it on the main camera; this will force the gun to rotate with the camera. This is what the gun looks like on my First Person Controller object:

Next, drop a sphere; you can leave it as is, but I have put a material on it with a red diffuse color. Now drop the itemSelf script on it. These are the values that I have given to it:

Create a new prefab and name it Potion; now drop the sphere that you created on the prefab. You now have a prefab for health potions! Place two of these onto the map. Currently, you can't do anything with these potions, but later we will let the player pick them up.