void SaveProgress()
    {
        PlayerProgress currLevelProgress = new PlayerProgress(
            levelMode,
            levelNo,
            starPercent,
            timePassed,
            wrongTries,
            nextNumber,
            true,
            false
            );

        ProgressController.SaveProgress(currLevelProgress);

        // If there is no level or we could not get one star, do not unlock next level.
        if (levelNo == levels.Count || starPercent < starPercents[0])
        {
            UICont.DisableNextButton();
            return;
        }

        // We have a next level, so unlock it.
        PlayerProgress nextLevelProgress = ProgressController.GetProgress(levelMode, levelNo + 1);

        nextLevelProgress.locked = false;

        ProgressController.SaveProgress(nextLevelProgress);
    }