я решил проблемку.
Код:
void Update ()
{
var mousePosition = Input.mousePosition;
mousePosition = Camera.main.ScreenToWorldPoint(mousePosition);
mousePosition.y = Mathf.Clamp(mousePosition.y, zMiN, zMAX);
var angle = Vector2.Angle(Vector2.right, mousePosition - transform.position);
transform.eulerAngles = new Vector3(0f, 0f, Mathf.Clamp(transform.position.y < mousePosition.y angle : -angle, zMiN, zMAX));
}