In Army of Ages our world is invaded by aliens. While in the Stone Age, you'll build clubbers, sling men and pre-historical dragonlike creatures to battle the different types of aliens creatures which crawl, walk and fly to your base. Once you gain enough experience points, you can upgrade to the next era: Medieval, Renaissance and so on and so forth.
View is 2D with your base to the far left and the enemy base to the far right. Units just walk on until fighting distance, where they will fight until dead. Units are automatically built after the correct building has been placed (like: sling men tent) and the player then mostly has to concentrate on (re)building turrets and unit spell like effects, like meteorite (Stone Age and further), Rain Hail (Medieval and further) etc.