Get on the roof of the left base, which is near the only gate they try to break down. Use Marksman turrets and Atomizer gravity wells to keep them from getting too close to the door. Also throw some hedgehogs to act as mines. If there are too many for the Marksman or Deadeye, use the Wildfire"s primary and secondary fire to eliminate large crowds. If you cannot see more enemies, use the Auger to pick off the last of them. Note: The gate must not be allowed to fall.