Coding is not right

private bool gameStarted = false;
[SerializeField]
private Texture gameStateText;
[SerializeField]
private GameObject player;
[SerializeField]
private BirdMovement birdMovement;
[SerializeField]
private FollowCamera followCamera;
private float restatDelay = 3f;
private float restartTimer;
private PlayerMovement playerMovement;
private PlayerHealth playerHealth;

// Use this for initialization
void Start () {
    Cursor.visible = false; 

    //.. Prevent the plaer from moving at the start of the game
    playerMovement.enabled = false;

    // Prevent the bird from moving at start of the game
    birdMovement.enabled = false;

    //Prevent the follow camera from moving to its game position
    followCamera.enabled = false; }



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

        // If the game is not styarted anmd press the space bar..
        if (gameStarted == false && Input.GetKeyUp (KeyCode.Space)) {

            //...Start the game
            StartGame();


            // ...Incremeate a Timer to count up to restarting...
            restartTimer = restartTimer + Time.deltaTime;

            //..and if it it reaches the restart delay

        if (restartTimer >= restatDelay) {

            //...then reload the currently loaded scene
            SceneManager.LoadScene (SceneManager.GetActiveScene ().buildIndex);

            }


    }

    private void StartGame(){
    //Set Game state
    gameStarted = true;

    // Remove the start text
    gameStateText.color = Color.white;

    //Alow the player to Move
    playerMovement.enabled = true;

    //Alow bird to move
    birdMovement.enabled = true;

    // Allow the camera to move
    followCamera.enabled = true;

private void Endgame() {

    //Set the game State
    gameStarted = false;

    // Show the game over Text
    gameSateText.color = Color.white;
    gameStateText.Text = "Game Over!";

    // Remove the player from the game
    player.SetActive (false);

}