The stone age, the bronze age, the dark ages, the steam ages, and the diesel age were all terrible times of conflict and struggle. Throughout the history of humankinds decimation and domination of this planet there has been one common denominator: we fight over resources and that fight drives the development of new technology.  First it was stick and stones, then those sticks and stones became bows, arrows, and spears. Then axes, knives, and swords made of flint. At some point i feel like there were catapults. Then gunpowder and very rudimentary cannons and muskets and stuff. And through all of it we fought for resources and domination. But now the future is here. The sky looks liike a scene from Blade Runner 2049 and there are all kinds of cool futuristic resources like crystals, rubies, plasma diamonds, and quantum emeralds that can be used for everything from weapons to energy production and even conquering death itself. We are still fighting wars for these resources but now we are using steel. Hence, the age of steel. Because this is the age we are in and what we are primarliy fighting with. Defend your base and the few resources you've been able to scrounge together as you optimize your strategies to fight of wave after wave of enemies who are intent on stealing your crystals. Build, deploy, upgrade and destory!