After the events of "100T Earth Defender" and "Exsilium", the Earth is under alien attack! All out of a sudden, unknown alien lifeforms started a global invasion on Earth! To counter the new crisis, heavily armed cities called "Anti-Extraterrestrial Threat Strategic Metropolis" had arisen. As the commander of the security forces in one of these cities, you have to build up the O' Pi Team and defeat invading alien lifeforms and protect the Earth! Features: - A classic tower defense game with few twists to give a whole new experience! - Simple gameplay mechanics fits for casual plays. - Proceed through missions and unlock new characters with their own specialities! - Upgrade troopers and facilities to gain the upper hand! - Full storyline included! Follow the daily routine of the O' Pi Team and protect the Earth from alien invasions!