not fix yet

Assets/Scripts/BackgroundChanger.cs

@@ -4,76 +4,71 @@ using UnityEngine;
 
 public class BackgroundChanger : MonoBehaviour {
 
-    private List<GameObject> backgroundGroup = new List<GameObject>();
-    private List<GameObject> obstacleGroup = new List<GameObject>();
-    private GameObject[] gameObjectGroup;
-    private GameObject background;
-    private GameObject obstacle;
-    private string[] colors = {"Blue", "Green" };
-        
-    public void Start()
-    {
-        CollectBackgrounds();
-        CollectObstacles();
-        UpdateBackgroud(colors[0]);
-    }
+	private List<GameObject> backgroundGroup = new List<GameObject>();
+	private List<GameObject> obstacleGroup = new List<GameObject>();
+	private GameObject[] gameObjectGroup;
+	private GameObject background;
+	private string[] colors = {"Blue", "Green" };
 
-    private void CollectBackgrounds()
-    {
-        foreach(string color in colors)
-        {
-            background = GameObject.FindWithTag(color + "Background");
-            backgroundGroup.Add(background);
-        }
-    }
+	public void Start()
+	{
+		CollectBackgrounds();
+		CollectObstacles();
+		UpdateBackgroud(colors[0]);
+	}
 
-    private void CollectObstacles()
-    {
-        foreach(string color in colors)
-        {
-            obstacle = GameObject.FindWithTag(color + "Obstacle");
-            obstacleGroup.Add(obstacle);
-        }
-    }
+	private void CollectBackgrounds()
+	{
+		background = GameObject.FindWithTag("Background");
+	}
 
-    public void Update()
-    {
-        if (Input.GetKey(KeyCode.X))
-        {
-            UpdateBackgroud("Blue");
-        } else if (Input.GetKey(KeyCode.Z))
-        {
-            UpdateBackgroud("Green");
-        }
-    }
+	private void CollectObstacles()
+	{
+		foreach(string color in colors)
+		{
+			gameObjectGroup = GameObject.FindGameObjectsWithTag(color + "Obstacle");
+			foreach(GameObject obstacle in gameObjectGroup)
+			{
+				obstacleGroup.Add(obstacle);
+			}
+		}
+	}
 
-    public void UpdateBackgroud(string tagColor)
-    {
-        foreach(GameObject background in backgroundGroup)
-        {
-            if (background.tag == tagColor + "Background")
-            {
-                background.SetActive(true);
-            } else
-            {
-                background.SetActive(false);
-            }
-        }
+	public void Update()
+	{
+		if (Input.GetKey(KeyCode.X))
+		{
+			UpdateBackgroud("Blue");
+		} else if (Input.GetKey(KeyCode.Z))
+		{
+			UpdateBackgroud("Green");
+		}
+	}
 
-        UpdateObstacle(tagColor);
-    }
+	public void UpdateBackgroud(string tagColor)
+	{
+		if(tagColor == "Green")
+		{
+			background.GetComponent<SpriteRenderer>().color = new Color32(46, 204, 113, 255);
+		} else if (tagColor == "Blue")
+		{
+			background.GetComponent<SpriteRenderer>().color = new Color32(65, 131, 215, 255);
+		}
 
-    private void UpdateObstacle(string tagColor)
-    { 
-        foreach (GameObject obstacle in obstacleGroup)
-        {
-            if(obstacle.tag == tagColor + "Obstacle")
-            {
-                obstacle.SetActive(false);
-            } else
-            {
-                obstacle.SetActive(true);
-            }
-        }
-    }
+		UpdateObstacle(tagColor);
+	}
+
+	private void UpdateObstacle(string tagColor)
+	{ 
+		foreach (GameObject obstacle in obstacleGroup)
+		{
+			if (obstacle.tag == tagColor + "Obstacle")
+			{
+				obstacle.SetActive(false);
+			} else
+			{
+				obstacle.SetActive(true);
+			}
+		}
+	}
 }

ProjectSettings/TagManager.asset

@@ -8,6 +8,7 @@ TagManager:
   - GreenBackground
   - BlueObstacle
   - GreenObstacle
+  - Background
   layers:
   - Default
   - TransparentFX

colourful-love.userprefs

 <Properties StartupItem="Assembly-CSharp.csproj">
   <MonoDevelop.Ide.Workspace ActiveConfiguration="Debug" PreferredExecutionTarget="Unity.Instance.Unity Editor" />
-  <MonoDevelop.Ide.Workbench ActiveDocument="Assets\Scripts\PlayerController.cs">
+  <MonoDevelop.Ide.Workbench ActiveDocument="Assets\Scripts\BackgroundChanger.cs">
     <Files>
-      <File FileName="Assets\Scripts\BackgroundChanger.cs" Line="32" Column="2" />
-      <File FileName="Assets\Scripts\PlayerController.cs" Line="14" Column="3" />
+      <File FileName="Assets\Scripts\BackgroundChanger.cs" Line="22" Column="1" />
+      <File FileName="Assets\Scripts\PlayerController.cs" Line="1" Column="1" />
       <File FileName="Assets\Scripts\PhysicObject.cs" Line="1" Column="1" />
       <File FileName="Assets\Scripts\SceneLoader.cs" Line="1" Column="1" />
     </Files>