added sounds

Assets/Scripts/ScoreService/ScoreService.cs

@@ -1,9 +1,10 @@
+using System;
 using UnityEngine;
 
 public class ScoreService
 {
     public int score=0;
-    public int highScore=0;
+    public int highScore=PlayerPrefs.GetInt("HighScore",0);
 
     public void AddScore()
     {
@@ -18,6 +19,7 @@ public class ScoreService
     {
         highScore = score;
         PlayerPrefs.SetInt("HighScore", highScore);
+        PlayerPrefs.Save();
     }
 
 }