/// <summary>
        /// LoadContent will be called once per game and is the place to load
        /// all of your content.
        /// </summary>
        protected override void LoadContent()
        {
            // Development Version 1.0.3
            // Create a new SpriteBatch for Drawing All Textures and a Font for Highscores
            // Requirements 4.3.7, 10.2.6, 11.1.0 and 13.3.0
            spriteBatch = new SpriteBatch(GraphicsDevice);
            font = Content.Load<SpriteFont>("HighscoresFont");

            // Development Version 1.0.3
            // Set Preferred Screen Ratio/Size
            // Requirement 4.0.0
            graphics.PreferredBackBufferWidth = screenWidth;
            graphics.PreferredBackBufferHeight = screenHeight;
            graphics.ApplyChanges(); //commit above screen changes
            IsMouseVisible = true; //set mouse visible

            // Development Version 2.0.0
            // Load Menu Content
            // Requirements 4.3.0, 4.3.1, 4.3.2, 4.3.3, 4.3.4 and 4.3.6
            loadMainMenu();
            loadHighScoreMenu();
            loadHelpMenu();
            loadCustomizeMenu();
            backButton = new mButton(Content.Load<Texture2D>("Buttons/BackButton"), graphics.GraphicsDevice);
            backButton.setSize(new Vector2(54, 24)); //image size is 54x24 pixels, size is halved
            backButton.setPosition(new Vector2(25, 25));

            // Development Version 2.0.4
            // Add Menu Selection and Zombie Sound Effects to Menus
            // Requirements 7.6.0, 7.6.1 and 7.6.2
            menuSelection = Content.Load<SoundEffect>("Sound/Selection");
            zombieSelection = Content.Load<SoundEffect>("Sound/ZombieSound1");

            // Development Version 3.0.2
            // Create Level System
            // Requirement 5.8.0
            levelSystem = new Level(graphics, Services, spriteBatch, this);
        }
 // Development Version 1.0.2
 // Reset Game
 // Requirement 16.0.0
 public void resetGame()
 {
     currentGameState = GameState.MainMenu;
     level = 0; // Set level back to 0
     levelSystem = new Level(graphics, Services, spriteBatch, this);// Create level system
 }