anchor.diff:    // Game state
     int _numFrames = 0;
     bool _isGameOver = false;
  +  int _gameOverFrame;
     int _currentLevel = 0;
   
     // Heads up display
  
positive.code: 
      // Add an explosion
      addExplosion(AsteroidSize.large, _ship.position);
  
      _navigator.pop();
    }
  
    // Handling controls
  
negative.code: 
      // Set game over
      _isGameOver = true;
      _gameOverFrame = _numFrames;
      _gameOverCallback(_hud.score);
  
      // Remove the ship
  