Unity3d GameJolt API Manager

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

public class GameJoltAPIManager : MonoBehaviour {
    public int gameID;
    public string privateKey;
    public string userName = "";
    public string userToken = "";
    [HideInInspector]
    public bool
        loggedIn = false;

    public float sessionPingTime = 15f;
    private float sessionTimer = 15f;

    public ArrayList achievedTrophies = new ArrayList();

    public static GameJoltAPIManager I { get; private set; }

    void Awake() {
        if (I != null && I != this) {
            DestroyImmediate(gameObject);
        }
        I = this;
        DontDestroyOnLoad(gameObject);
    }

    void Start() {
        GJAPI.Init(gameID, privateKey);
        GJAPI.Users.VerifyCallback += OnVerifyUser;
        GJAPI.Sessions.CloseCallback += OnSessionClose;
        GJAPI.Trophies.GetAllCallback += OnTrophyGetAll;
        if (userName == "" && userToken == "") {
            GJAPIHelper.Users.ShowLogin();
        } else {
            GJAPI.Users.Verify(userName, userToken);
        }
    }

    void OnVerifyUser( bool success ) {
        if (success) {
            Debug.Log("Successfully logged in.");
            GJAPI.Trophies.GetAll(true);
            GJAPI.Sessions.Open();
            loggedIn = true;
        } else {
            Debug.Log("Failed to log in.");
        }
    }

    void OnSessionClose( bool success ) {
        Application.Quit();
    }

    void Update() {
        if (loggedIn) {
            sessionTimer -= Time.deltaTime;

            if (sessionTimer <= 0) {
                GJAPI.Sessions.Ping();
                sessionTimer = sessionPingTime;
            }
        }
    }

    void OnTrophyGetAll( GJTrophy[] trophies ) {
        for (int i = 0; i < trophies.Length; i++) {
            achievedTrophies.Add(trophies[i].Id);
        }
        AddTrophy(8220);
    }

    public void AddTrophy( uint Id ) {
        GJAPI.Trophies.Add(Id);
        if (!achievedTrophies.Contains(Id)) {
            GJAPIHelper.Trophies.ShowTrophyUnlockNotification(Id);
            achievedTrophies.Add(Id);
        }
    }

    void OnApplicationQuit() {
        if (loggedIn) {
            GJAPI.Sessions.Close();
            Application.CancelQuit();
        }
    }
}