void Start()
        {
            foreach (var singlePlayerButton in singlePlayerButtons)
            {
                singlePlayerButton.onClick.AddListener(SceneLoader.instance.GoToSingleplayerMenu);
            }

            mainMenuButton.onClick.AddListener(SceneLoader.instance.GoToMainMenu);
            campaignMenuDropdown.ClearOptions();

            var campaigns = CampaignManager.instance.availableCampaigns.Select(campaign => campaign.campaignName).ToList();

            selectedCampaignSequence   = CampaignManager.instance.availableCampaigns.First();
            selectedCampaignDifficulty = CampaignDifficulty.Normal;

            campaignMenuDropdown.AddOptions(campaigns);
            campaignMenuDropdown.onValueChanged.AddListener(delegate {
                UpdateSelectedCampaign();
            });

            campaignDifficultyDropdown.ClearOptions();
            campaignDifficultyDropdown.AddOptions(Enum.GetNames(typeof(CampaignDifficulty)).ToList());
            campaignDifficultyDropdown.value = 1;

            campaignDifficultyDropdown.onValueChanged.AddListener(delegate {
                UpdateSelectedDifficulty();
            });

            goButton.onClick.AddListener(StartCampaign);
        }
        private void UpdateSelectedDifficulty()
        {
            var selectedIndex = campaignDifficultyDropdown.value;

            switch (selectedIndex)
            {
            case 0:
                selectedCampaignDifficulty = CampaignDifficulty.Easy;
                break;

            case 1:
                selectedCampaignDifficulty = CampaignDifficulty.Normal;
                break;

            case 2:
                selectedCampaignDifficulty = CampaignDifficulty.Hard;
                break;

            case 3:
                selectedCampaignDifficulty = CampaignDifficulty.Lunatic;
                break;
            }
        }