Farms are vital in this game, as they allow the player to build additonal units. When built, four more ordinary Units, and one more Special Unit, may be built. Up to four Farms can be built at one time, but in certain levels the player is able to build four and then claim the farms generated in the level for the mission, but the unit cap will still act as though you had four farms. At least one farm must be built in order to build a Shipyard or Special Factory, along with a Barracks. The extra Full Unit Cap gives the player unit caps as though they had four farms, but at least one must be built in order to build either of the above buildings anyway.