[samuele55598@gmail.com]

Ecco l'intero script:
using UnityEngine;
using System.Collections;

public class Movement : MonoBehaviour {

public float moveSpeed;
public GameObject particle;

// Use this for initialization
void Start () {

}

// Update is called once per frame
void Update () {

if (Input.GetKey(KeyCode.W))
{
transform.Translate(Vector3.forward * Time.deltaTime*moveSpeed);
Ray ras = new Ray(transform.position,Vector3.forward);
Debug.DrawRay(ras.origin, ras.direction * 10, Color.yellow);
}

if (Input.GetKey(KeyCode.S))
{
transform.Translate(-Vector3.forward * Time.deltaTime*moveSpeed);

}

if (Input.GetKey(KeyCode.A))
{
transform.Translate(-Vector3.right * Time.deltaTime*moveSpeed);

}

if (Input.GetKey(KeyCode.D))
{
transform.Translate(Vector3.right * Time.deltaTime*moveSpeed);
}

if (Input.GetButtonDown("Fire1")) {
Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);

if (Physics.Raycast(ray)){

Instantiate(particle, transform.position, transform.rotation);

}

}

}
}