2D Tower Defense Tutorial -- Sprite Rotation

No Error codes. I'm a noob. What am I doing wrong?

Tutorial Location

I'm sure there's a more basic approach. Appreciate the time!

using UnityEngine; using System.Collections;

public class MoveEnemy_A : MonoBehaviour {

 [HideInInspector]
 public GameObject[] waypoints_A;
 private int currentWaypoint = 0;
 private float lastWaypointSwitchTime;
 public float speed = 1.0f;

 void Start()
 {
     lastWaypointSwitchTime = Time.time;
 }


 void Update() {
     transform.Translate (0, 0, Time.deltaTime * 1);



     //1
     Vector3 startPosition = waypoints_A [currentWaypoint].transform.position;
     Vector3 endPosition = waypoints_A [currentWaypoint + 1].transform.position;
     //2
     float pathLength = Vector3.Distance (startPosition, endPosition);
     float totalTimeForPath = pathLength / speed;
     float currentTimeOnPath = Time.time - lastWaypointSwitchTime;
     gameObject.transform.position = Vector3.Lerp (startPosition, endPosition, currentTimeOnPath / totalTimeForPath);
     //3
     if (gameObject.transform.position.Equals (endPosition)) {
         if (currentWaypoint < waypoints_A.Length - 2) {
             // 3.a
             currentWaypoint++;
             lastWaypointSwitchTime = Time.time;

             RotateIntoMoveDirection();

         } else {
             //3.b
             Destroy(gameObject);
             //TODO: deduct health
         }
     }
 }
 // rotate enemies

 private void RotateIntoMoveDirection() {
     //1
     Vector3 newStartPosition = waypoints_A [currentWaypoint].transform.position;
     Vector3 newEndPosition = waypoints_A [currentWaypoint + 1].transform.position;
     Vector3 newDirection = (newEndPosition - newStartPosition);
     //2
     float x = newDirection.x;
     float y = newDirection.y;
     float rotationAngle = Mathf.Atan2 (y, x) * 180 / Mathf.PI;
     //3
     GameObject sprite = (GameObject)
         gameObject.transform.FindChild("Sprite").gameObject;
     sprite.transform.rotation = 
         Quaternion.AngleAxis(rotationAngle, Vector3.forward);
 }

}