Give more details. What does not work in “Admin menu blocking” add-on?
The 1st thing I see in “Mark New Posts” – it adds its’ submenu item to the “Settings” menu with ‘administrator’ role ID instead of ‘manage_options’ user capability. Thus this menu item is available to the user with ‘administrator’ role only.
mark-new-posts.php:244: add_options_page(self::PLUGIN_NAME, self::PLUGIN_NAME, 'administrator', basename(__FILE__), array(&$this, 'display_options_page'));