Pull the gate up in this defense game and make sure none of the attackers makes it through. You will be in charge of keeping the fortress secure as you are under siege from a race of barbarians. Use the cannon to shoot and hire units to fight.
It is time to be evil and destroy the human world. Use your underground fortress to build a tower and emerge from the ground to cast the ultimate destruction spell. Be careful though! These puny little humans will try to stop you.