Playing as Alexander you can get 2 achievements:
75. The Man Who Would Be King. Beat the game on any difficulty setting as Alexander.
76. Conquest of the World. As Alexander, defeat every known player by 350 BC.
It’s a bit harder than I thought, to get it I setup a game duel size map – Pangaea. Basically I started to look where my opponent was settled, then I created 5 cities as soon as possible, last one was found as close as possible to the other nation’s capital.
Once I got iron I upgraded at least 6 warriors that were fortified in the border, these 6 plus an archer were able to take all 3 cities before 350 and unlock the achievement.