I think I built two cannons, two or three mortars, and a terp before moving, but the terp and one cannon had to finish early.
Then I flew the terp over to expand the flat ground enough for a CN, and then a tiny bit of wall while the Cannon guarded.
The CN and other guns picked up what charge I would from the sacrificial Collectors in the start-area.
(With that said, it's still possible that it's a different map with a similar screenshot.)
