I played a campaign today with three AI.
The game didn't end when I supposedly had destroyed all visible structures.
I accidentally killed a hidden structure on the northwest side of the map with a lucky weatherstorm.
The debug menu revealed the second building's location, see below at the cursor:
Also of note, both of these structures were defensive structures, which the units in the area would not auto-target with Attack-Move.
I played a campaign today with three AI. The game didn't end when I supposedly had destroyed all visible structures. I accidentally killed a hidden structure on the northwest side of the map with a lucky weatherstorm. The debug menu revealed the second building's location, see below at the cursor:
Also of note, both of these structures were defensive structures, which the units in the area would not auto-target with Attack-Move.