Updated Destroy By Contact Script

using UnityEngine;
using System.Collections;

public class DestroyByContact : MonoBehaviour 
{
    public GameObject explosion;
    public GameObject playerExplosion;
    public int scoreValue;
    private GameController gameController;

    void Start ()
    {
        GameObject gameControllerObject = GameObject.FindGameObjectWithTag ("GameController");
        if (gameControllerObject != null)
        {
            gameController = gameControllerObject.GetComponent <GameController>();
        }
        if (gameController == null)
        {
            Debug.Log ("Cannot find 'GameController' script");
        }
    }

    void OnTriggerEnter(Collider other)
    {
        if (other.tag == "Boundary")
        
        {
            return;
        }
        Instantiate (explosion, transform.position, transform.rotation);
        if (other.tag == "Player") {
            Instantiate (playerExplosion, other.transform.position, other.transform.rotation);
            gameController.GameOver ();
        }

        gameController.AddScore (scoreValue);
        Destroy (other.gameObject);
        Destroy (gameObject);
    }
}