The second counterattack bonus mission brings us again back to the Eastern Mediterranean for another 20 waves of even stronger naval and air units. You will begin this mission with the turrets you had built at the end of the previous level and an enemy bomber will come and open up a third route of attack for naval vessels to approach from, destroying the bridge that connected the largest island to the mainland along with anything on the smallest island.
With having all upgrades unlocked at this point and the significant numbers of waves in the missions that follow, it becomes a strategically viable option to get to having 3 level three Comms turrets as soon as possible while accruing 150$ saved up at the end of every level. Doing this allows you to get the maximum bonus interest of 50$ per wave. From here on out this becomes a recurring strategy.
From the beginning waves up to wave 10 you should focus primarily on getting the full interest bonus from three fully upgraded Communications towers while filling out any open spots on the north and south main land. Cannons are the way to go here, maybe a few extra Machine Gun turrets, but only one additional Anti Air should be required, placed on the largest island under their flight path.
On the way up through wave 20 you should be reaching the point where you have packed turrets into every space possible, making sure you have Comms inside of clusters of turrets whenever possible to boost their range and firepower, even if already earning max interest.