In the great gorge, very valuable resources are extracted, which are necessary for the construction of military equipment and research. At this depth, terrible monsters live, which will try to prevent the prey. In the center is your main base, and around the circle attack monsters. To provide protection, install quick-firing cannons, which destroy the approaching enemies. Cannons have a different category from simple to more modern, which open after a certain wave. For each it will be necessary to pay a certain amount of money, so the weapons can be improved so that they become more powerful and could destroy larger monsters.