Vanguard Wars

All people panic! The aliens have invaded the land, all the soldiers in terror, and can not fight. The only thing that can protect all of humanity is fighting towers. They are motorized and require no intervention from the people. Build houses to repel waves of enemies and do not let the enemy get into the ground. In the background, you can see the town upside down. From this, we can see that all the guns are at the bottom of the ship earth.