Creeper World: Anniversary Edition

Imagine an enemy that is everywhere and moves like a giant, organic mass across the map.
Imagine your base and your people surrounded by a blanket of crushing destruction from all directions. Your only hope, well what hope?
Then you take the high ground and pound this enemy into oblivion. You've saved the day just so you can do it again and again. Do you have what it takes to save your great city and all of history?