AS 3.0 code up to Win/Lose Screen

package  {

import flash.media.Sound;
import flash.display.MovieClip;
import flash.events.Event;

public class Main extends MovieClip {
var score = 0;
   var health = 100;
   var collectSound : Sound = new CollectSound();

public function Main(){

stage.addEventListener(Event.ENTER_FRAME, gameLoop);
stage.addChild(player);

gameOverScreen.visible = false;
    winScreen.visible = false;

}
function gameLoop(evt:Event)
{
     player.x = stage.mouseX;
player.y = stage.mouseY;
background.x = background.x - 7;

level.x = level.x - 7;
goal.x = goal.x - 7;

for(var i = 0; i < level.numChildren; i++)
{
   if(level.getChildAt(i).name == "collectable" && player.hitTestObject(level.getChildAt(i)) && level.getChildAt(i).visible == true)
{

   level.getChildAt(i).visible = false;
   score += 10;
   collectSound.play();


        }
   if(level.getChildAt(i).name == "enemy" && player.hitTestObject(level.getChildAt(i)) && level.getChildAt(i).visible == true){
level.getChildAt(i).visible = false;
health -= 20;
        }
}
        scoreDisplay.text = "Score: " + score;
   healthDisplay.text = "Health: " + health;

        if(player.x > goal.x && gameOverScreen.visible == false)
        {
            winScreen.visible = true;
        }
     
        if(health <= 0 && winScreen.visible == false)
        {
            gameOverScreen.visible = true;
        }
     
    }

}

}