How to end my game on destruction of all brick objects?

I’m having a problem that probably only in experienced programmers will face. I cant think of a way to end my game once all of my bricks are destroyed. I have a gameOver() method but I don’t know how to make it game over once all of my bricks are destroyed. Does anyone have any suggestions or easy tips to do this. Here is a snippet of relevant code:

private var score : int=0;
var breakCombo : boolean = false; 
var guiScore : GUIText;

 var blue : Texture;

 var isBlue : boolean = false; 
 
 var particle3 :boolean = false;
 
 var brickPieces : ParticleSystem;
 
  var brickPieces2 : ParticleSystem;

 var timeLv1 : GUIText;
 var timer : float = 30;
 var outOfTime : boolean = false;
  
function level1 () {
   
    timer -= Time.deltaTime;
    
    timeLv1.text= "Time: " + timer.ToString("f0");
    if(timer <= 0){
    
    timer = 0;
    outOfTime = true; 
    }
     }

function Start () {

guiScore.text="Score: 0";
}

function Awake(){
rigidbody.velocity.x = 2;
rigidbody.velocity.y = -13;
}

function Update () {
if(Application.loadedLevelName == "firstGame"){
level1();
if(outOfTime){
GameOver();
}
if(transform.position.y < -7){
GameOver();
}
}
}

function OnCollisionEnter(col : Collision){

if(col.collider.name == "Brick3"){
Instantiate(brickPieces,transform.position,transform.rotation);
brickPieces.Play();
particle3 = true;
Destroy(col.gameObject);
score += 10;
guiScore.text= "Score: " + score;
breakCombo = false;
renderer.material.mainTexture = blue;
isBlue = true;
}
if(col.collider.name == "Brick2" && isBlue == true){
Instantiate(brickPieces2,transform.position,transform.rotation);
brickPieces2.Play();
Destroy(col.gameObject);

if(!breakCombo){
score=(score+10)*2;
}
else{

score += 10;
}
breakCombo = false;
guiScore.text= "Score: " + score;
print("collided with brick");
}
if(col.collider.name == "paddle"){
breakCombo=true;
}
}

function GameOver(){
//save high score
if(score > PlayerPrefs.GetInt("brickScore")){
PlayerPrefs.SetInt("brickScore", score);
}
else{
PlayerPrefs.SetInt("brickScore", score);
}
Application.LoadLevel("Menu");
}

What you want is an array! Store references to all of your bricks inside the array, and then when they are all null, run your gameover().