Frontline Defense: Special Ops is a challenging expansion pack for Frontline Defense 2, featuring 14 new missions. In each mission, your task is to prevent enemy vehicles and infantry from reaching the end of a path by building various towers. Each tower's damage, range and rate of fire can be upgraded. If enough enemies make it to the end of the path, you will fail the mission. If you complete a mission, you will gain credits, which you can spend on new towers.