After following the last two videos on creating the game start and end components, when I press run, movement occurs

private bool gameStarted = false;

[SerializeField]
private Text gameStateText;

[SerializeField]
private GameObject player;

[SerializeField]
private BirdMovement birdMovement;

[SerializeField]
private FollowCamera followCamera;

private float restartDelay = 3f;
private float restartTimer;
private PlayerMovement playerMovement;
private PlayerHealth playerHealth;

// Use this for initialization
void Start ()
{

    Cursor.visible = false;

    playerMovement = GetComponent<PlayerMovement>();
    playerHealth = GetComponent<PlayerHealth>();

    //we need to prevent the player from moving at the start of the game
    playerMovement.enabled = false;
    birdMovement.enabled = false;
    followCamera.enabled = false;
}

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

    //if the game is not started and the player presses the spacebar then start the game
    if (gameStarted == false && Input.GetKeyUp(KeyCode.Space))
    {
        StartGame();
    }
    //if player is no longer alive
    if (playerHealth.alive == false)
    {
        //end the game
        EndGame();

        //increment a timer to count up from restarting
        restartTimer = restartTimer + Time.deltaTime;

        //and if it reaches the restart delay
        if (restartTimer >= restartDelay)
        {
            //reload the currently loaded level
            Application.LoadLevel(Application.loadedLevel);
        }
    }//end endgame  if block


}

private void StartGame()
{
    //set game start 
    gameStarted = true;
    gameStateText.color = Color.clear;

    playerMovement.enabled = true;
    birdMovement.enabled = true;
    followCamera.enabled = true;

}

private void EndGame()
{

    gameStarted = false;

    //set game text to game over
    gameStateText.color = Color.white;
    gameStateText.text = "Game Over!";

    //remove the player from the game
    player.SetActive(false);
}