var mousePosition = Input.mousePosition;  
      mousePosition = Camera.main.ScreenToWorldPoint (mousePosition);  
      if (mousePosition.y < Y_КООРДИНАТА_НАЧАЛА_КРАСНОЙ_ЗОНЫ) {
           var angle = Vector2.Angle (Vector2.right, mousePosition - transform.position);  
           transform.eulerAngles = new Vector3 (0f, 0f, transform.position.y < mousePosition.y ? angle : -angle);
      }

var touches = Input.touches;
for(var i = 0; i < Input.touchCount; i++){
  var t = touches[i];
    if (t.position.y < Y_КРАСНОЙ_ЗОНЫ) {
      var angle = Vector2.Angle (Vector2.right, t.position - transform.position);   
         transform.eulerAngles = new Vector3 (0f, 0f, transform.position.y < t.position.y ? angle : -angle);
     }
}