Mission number seven in the Axis campaign now has you facing a total of forty waves of enemies, all approaching from three different paths from the Southwest. Naval vessels will start off the level but make sure you are prepared for wave 20 when the aircraft show up.
Turret placement should focus on utilizing the space closest to where the paths meet towards the east of the map along the tiny island where the paths converge.
The first turrets placed should be two Machine Gun turrets on the small island on the bottom right and top left spaces. The third top right space should be occupied by an Inferno after both those Machine Guns and a third by the convergence are upgraded to max level.
Wave 20 brings with it enemy aircraft, thus placing a level one AA turret should be a top priority at the end of wave 19. Prior to that, build some Cannons on the north and south sides of the convergence area. From level 20 through thirty work on getting a 2nd level X-Weapon with max boost while working on more Cannon and AA as needed.
As you reach the final stretch of waves towards the final challenges, save up for a second X-Weapon and place it somewhere it can get a decent boost from nearby turrets. There will be a counterattack here in a future level so its worth building up as much as possible, even if already overpowering the enemy. If you can, try to sell the small island’s turrets right before completing the mission and use them to build something else, as these will be destroyed in the opening moments of the Counterattack.
Victory Point Spending
Mostly everything is maxed out at this point with 3 options left to choose and two points to spend. I decided to go with the 2nd levels of the X-Weapon and Repair, since 2nd level Firestorms still serve their purpose quite well. At this point the Firestorm is the only thing not at level 3 (2).