4 player map that utilizes both Challenge #1 and Challenge #2. Though the Main bases are close by air, they're also fairly inaccessible.
Destructable/Collapsable Water Tower that is within range of the main that allows for the "Back Door" to be closed. Choice of 3rd will (likely) depend on opponent spawn.
Renegade Missile Turrets offer limited protection from Early-Game Air Harassment. Strategic Placement of Turrets requires micro to avoid.