Movement.cs (Original)

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Movement : MonoBehaviour {

    public float movementSpeed;

    // Use this for initialization
    void Start () {

    }

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

        if (Input.GetKey (KeyCode.LeftShift) && Input.GetKey ("w")) {
            transform.position += transform.TransformDirection (Vector3.forward) * Time.deltaTime * movementSpeed * 2.5f;
        }   else if (Input.GetKey ("w") && !Input.GetKey (KeyCode.LeftShift)) {
            transform.position += transform.TransformDirection (Vector3.forward) * Time.deltaTime * movementSpeed;
        }   else if (Input.GetKey ("s")) {
            transform.position -= transform.TransformDirection (Vector3.forward) * Time.deltaTime * movementSpeed;
        }

        if (Input.GetKey ("a") && !Input.GetKey ("d")) {
                transform.position += transform.TransformDirection (Vector3.left) * Time.deltaTime * movementSpeed;
            } else if (Input.GetKey ("d") && !Input.GetKey ("a")) {
                transform.position -= transform.TransformDirection (Vector3.left) * Time.deltaTime * movementSpeed;
            }
        }
}