gameManager.cs

using UnityEngine;
using UnityEngine.SceneManagement;


public class gameManager : MonoBehaviour
{

    [SerializeField] private string Difficulty = "NORMAL";

    #region Difficulty settings

    private void Awake()
    {
        Difficulty = PlayerPrefs.GetString("GameDifficulty", "NORMAL");
    }

    public void SetDifficulty(string newDifficulty)
    {
        Difficulty = newDifficulty;
        PlayerPrefs.SetString("GameDifficulty", newDifficulty);
        PlayerPrefs.Save();
    }

    public void SetEasy()
    {
        SetDifficulty("EASY");
    }
    public void SetNormal()
    {
        SetDifficulty("NORMAL");
    }
    public void SetHard()
    {
        SetDifficulty("HARD");
    }

    #endregion

    public void RestartLevel()
    {
        // Reloads the level
        SceneManager.LoadScene(SceneManager.GetActiveScene().name);
        Time.timeScale = 1f;
    }

    public void MainMenu()
    {
        // Loads main menu
        SceneManager.LoadScene("Start Menu");
        Time.timeScale = 1f;
    }

    public void LoadLastCheckpoint()
    {
        // load last checkpoint
        Time.timeScale = 1f;
    }

}