Ruin Them All Achievement in Age of Empires: Definitive Edition

Ruins are fixed controllable buildings on maps.

Start a Random map game with normal map, game speed fastest, any empire, normal AI, map all visible.

Quickly check the map to make sure there are ruins available to capture and also that there are none too close to the enemy town centre. If there are, spawn 5 cars using the 'bigdaddy' cheat 5 times. You'll then want to drive around and move them to a ruin each to capture it. Then simply defend them with the cars. This normally works best if you sent them to stand ground at the location. You'll want to ensure they don't attack the enemy base though as otherwise the enemy may resign before the end of the game. Now simply wait for the timer to count down and the achievement is yours. You could even use the time to work on the resource achievements.