BaseEntityNpc.cs

private void obtainScreenBounds() {
	float cameraToPlayerDistance = Mathf.Abs(Camera.mainCamera.transform.position.z - transform.position.z);
	minScreenBounds = Camera.main.ScreenToWorldPoint(new Vector3(0, 0, cameraToPlayerDistance));
	maxScreenBounds = Camera.main.ScreenToWorldPoint(new Vector3(Screen.width, Screen.height, cameraToPlayerDistance));
}

private void checkScreenBoundaries() {
	transform.position = new Vector3(
		Mathf.Clamp(transform.position.x, (minScreenBounds.x) + 1, (maxScreenBounds.x) - 1),
    		Mathf.Clamp(transform.position.y, (minScreenBounds.y) + 1, (maxScreenBounds.y) - 1), 
		transform.position.z);
}