Perimeter takes the RTS formula and turns it on its ear and then spanks it for good measure. The terrafoming of worlds in the game is also the way to get the land leveled up and ready for your buildings and structures, particularly your energy collectors which you need to power your buildings, build new units and deploy your massive force shield around your base (the Perimeter of the game's title). The shield is impenetrable but obviously takes a ton of energy to keep up. Terrafoming can also be used as a defensive measure, creating trenches and other obstacles around your base.