Game behavior

This is attached to an empty GameObject in the scene, as follows:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.SceneManagement;
using CustomExtensions;

public class GameBehavior : MonoBehaviour, IManager
{
    public string labelText = "Collect all 4 items and win your freedom!";
    public readonly int maxItems = 4;
    public bool showWinScreen = false;
    public bool showLossScreen = false;

    public delegate void DebugDelegate(string newText);
    public DebugDelegate debug = Print;

    private string _state;
    public string State 
    {
        get { return _state; }
        set { _state = value; }
    }

    private int _itemsCollected = 0;
    public int Items
    {
        get { return _itemsCollected; }
        set { 
            _itemsCollected = value;

            if (_itemsCollected >= maxItems)
            {
                labelText = "You've found all the items!";
                showWinScreen...