Time for action – pausing and restarting 

Since our game will need to be paused and restarted when a player wins or loses, this is a good time to use a namespace that isn't included in new C# scripts by default.

Add the following code to GameBehavior and play:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;

 // 1
 using UnityEngine.SceneManagement;

 public class GameBehavior : MonoBehaviour 
 {
     // ... No changes needed ...
 
     private int _itemsCollected = 0;
     public int Items
     {
         get { return _itemsCollected; }
         set { 
             _itemsCollected = value;
 
             if (_itemsCollected >= maxItems)
             {
                 labelText = "You've found all the items!";
                 showWinScreen = true;

                 // 2
                 Time.timeScale = 0f;
             }
             else
             {
                 labelText = "Item found, only " + (maxItems -
      ...