anchor.diff:      // Move objects to center camera and warp objects around the edges
       centerCamera();
       warpObjects();
  +
  +    // Check for level up
  +    if (_asteroids.length == 0) {
  +      _currentLevel++;
  +      setupLevel(_currentLevel);
  +    }
   
       // Update shield
       if (_numFrames > _numFramesShieldActive) _shield.visible = false;
  
positive.code:   SpriteSheet spriteSheetUI;
    Sprite sprtBgScore;
    Sprite sprtBgShield;
  
    int _score = 0;
  
  
negative.code:   // Game state
    int _numFrames = 0;
    bool _isGameOver = false;
    int _currentLevel = 0;
  
    // Heads up display
    Hud _hud;
  