The alien species Zuran have arrived are not planning to leave earth. Survive the chaos, the war! You daily goal is to keep alive. Build a base or wonder the city from one place to another. Living behind your walls is as hard as moving around, once the Zuran have spotted you expect more to come to hunt you down. They are organized and smart. Make sure you have enough defenses when they come for you if you have built a base. 

Alien bug swarms, machines and many tactics will be thrown your way. Gear up! and get ready as the end of the world is near. 

It came from above