Command Buildings
These buildings control major functions of day-to-day combat, planning and management of your units and base. They include Command HQ, Joint Ops Center, Logistics Exchange, Armoury, Tracking Center, Bunker, Medical Lab, and Training Center.
Resource Buildings
Resources are required for troop production and for sector development. The various Resource buildings you can build all manage different aspects of your Resource production and accumulation. Basically the more Resource buildings you have and the higher their level is, the more Resources you can produce, accumulate and spend. Resource buildings include Storage Depots, Field Kitchen, Air Traffic Control, Oil, Derrick, Arms Dealer and Munitions Factory.
Military Buildings
These buildings are needed to produce, manage, and deploy all of your combat units. Military buildings include Barracks, Combat Support Center, Airfield, Tank Depot, and Mercenary Bar.
Defensive Builings
Perimeter Defenses and Imporvements are the two types of Defensive builidngs you can purchase with Diamonds and Resources. Perimeter defensive buildings include Walls, Towers, Turrets, and Artillery. Improvements are for enhancing the grounds of your Sector and adding to your Perimeter Defense.