Homing Missiles!

Hello,
I am currently attempting to create a game that is a top down spaceship game. This game is an android made app that is similar to the “Missiles!” application currently on the Google Play Store. I have made the actual player (The space ship), but I am having immense trouble with the homing missiles that follow and try to destroy the player. I want the missiles to be like the one in the aforementioned “Missiles!” game. But I cannot recreate them even though I have went through multiple threads and videos about this. I am really stuck right now, and help would be greatly appreciated… I want this to be a 2D missile which follows a 2D character object, on a 2D background. But as I said, the missiles don’t currently work.
Thank you!

Here’s the code I created for a missile.

using UnityEngine;
using System.Collections;

public class Missile : MonoBehaviour {
	public float RangeTilShutdown;
	public int DamageToShields;
	public int DamageToHull;
	public GameObject ExplosionSmall;
	public Vector3 PositionSpawned;
	private GameObject[] Flares;
	private GameObject[] Hostiles;
	private GameObject MissileTarget;
	private bool Ready = false;

	void Start () {
		PositionSpawned = gameObject.transform.position;
		Flares = GameObject.FindGameObjectsWithTag ("Flare");
		Hostiles = GameObject.FindGameObjectsWithTag ("Hostile");
		if (Flares.Length > 0) {
			MissileTarget = Flares [0];
		} else if (Hostiles.Length > 0) {
			MissileTarget = Hostiles [0];
		}
	}

	void Update () {
		if (MissileTarget != null) {
			GetComponent<SlerpToLookAt> ().Target = MissileTarget.transform;
		} else {
			Destroy (gameObject);
		}
		if (Vector3.Distance (gameObject.transform.position, PositionSpawned) >= RangeTilShutdown) {
			Destroy (gameObject);
		}
	}

	void OnCollisionEnter(Collision Other) {
		ContactPoint Contact = Other.contacts [0];
		Quaternion Rot = Quaternion.FromToRotation (Vector3.up, Contact.normal);
		Vector3 Pos = Contact.point;
		Instantiate (ExplosionSmall, Pos, Rot);
		if (Other.gameObject.GetComponent<Shield> ().ComponentDisabled == false) {
			int TargetDamageVariance = Other.gameObject.GetComponent<Shield> ().DamageVariance;
			int DamageDealt = DamageToShields + Mathf.RoundToInt(Random.Range(-TargetDamageVariance, TargetDamageVariance));
			Other.gameObject.GetComponent<Shield> ().Power -= DamageDealt;
		} else if (Other.gameObject.GetComponent<HullIntegrity> ().ComponentDisabled == false) {
			int TargetDamageVariance = Other.gameObject.GetComponent<HullIntegrity> ().DamageVariance;
			int DamageDealt = DamageToHull + Mathf.RoundToInt (Random.Range (-TargetDamageVariance, TargetDamageVariance));
			Other.gameObject.GetComponent<HullIntegrity> ().Integrity -= DamageDealt;
		}
		Destroy (gameObject);
	}
}

This is SlerpToLookAt.cs:

using UnityEngine;
using System.Collections;

public class SlerpToLookAt: MonoBehaviour {
	public Transform Target;
	public float RotationSpeed;

	private Quaternion _LookRotation;
	private Vector3 _Direction;

	void Update () {
		_Direction = (Target.position - transform.position).normalized;
		_LookRotation = Quaternion.LookRotation (_Direction);
		gameObject.transform.rotation = Quaternion.Slerp (transform.rotation, _LookRotation, Time.deltaTime * RotationSpeed);
	}
}

Be sure to also attach SlerpToLookAt.cs onto the missile. Also attach rigidbody and constant force. On rigidbody, uncheck “Use Gravity”. On constant force, put the speed desired in the z axis of relative force. By the way, the flares gameobject is for antimissile flares. You can remove that if you want. I used this for a 3D game, but it probably can also work in 2D.