The final loop

CONTROLS:

Left mouse button to select towers.

A/D rotate towers and base clockwise and counterclockwise.

Middle mouse button to rotate the camera.

You are tasked with defending the final loop, humankind's last hope of survival.
Each round an alian ship will drop units and try to destroy your obalysk.
Build turrets and move your base around the loop to defense it and win the game.