All right, this is my time!
First I want to thank
Più Freddo for organization!
This is the first time for me winning on Deity! I recall, how I won on Emperor for the first time. There were tournaments on the Russian forum civfanatics.ru, I was playing them on Monarch regularly. And one day, 16 years ago, I thought "OK, I must select Emperor difficulty in the next tournament". And then the conditions of next tournament was announced: we play for Mongols, our single ally are Ottomans, and there are 5 or 6 European nations in the unbreakable alliance against us. Well, I still selected Emperor and won this game, first time in my civ-life.
Also, this is my 3rd completed COTM in a row (mostly thanks to the extended submission deadlines). After the experience of the Celts game (COTM 152), I relied much on igniting the war between the computers. And the wars I started in the early phase of the game (mostly, after attacking Vikings and calling Inca to help me for gpt), continued and extended to the whole continent. For example, the Spanish, after making peace with me, marched across my whole land to attack the Chinese and Babylonian cities on the shores.
While learning Chivalry I was gathering the power to attack by building horsemen and marketplaces. Once completed Chivalry, I put science to 0 and started upgrading the horsemen. As the first aim I selected the Spanish. There were 2 reasons:
1. my city cuture-flipped to them
2. I wanted to have safe back when turning to the rest of the continent
Having a Spanish city (which Isabella gave me for peace) helped a lot to build the base for the attack.
I got Chemistry from Spanish and they got a 20-turns delay until the final extermination. The next aim was the Viking. Fun, but they stayed in the game after loosing all the cities (looks like they had a settler on a galley somewhere)
Then I had doubts. Arabs didn't have iron, so, they could be an easy prey from my Keshiks, but they were friendly to me and were in alliance against the Spanish. So, I charged 1/4/1 Swiss mercenaries of Netherlands. Additional factor to attack the Dutch was that they owned the Temple of Artemis.
That war was much more difficult, but, anyway, possible. I experienced several culture-flips, but as I mostly did not keep Keshiks in the cities, I reconquered them. Got an army in that war, but after a few turns lost it in a not-so-suicidal attack. Once I overestimated my power and tried to capture 2 cities in one turn, resulting to a long-lasting stalemate situation on the fronts, while I was waiting for the reinforcements.
Finally, got Metallurgy from the Dutch. After a while I learned Military traditions and started upgrading my Keshiks to Cavalry. At that time Babylonians reached the Industrial age. And, again, I could really well leave them alone and conquer the weakest rivals. But there was no guarantee that the Babylon won't attack while I would be dealing with the Arabs. So, I started planning the Babylon campaign. They had hordes of units in the field.
I was really lucky that some 2 turns before I was ready to attack Babylon, Babylon declared war on Inca, and they started moving their troops to the opposite border. I waited for a couple more turns, till they drag more of their units to the Eastern front, and finally, attacked. I had around 90 cavalry at that time and 12 elite Keshiks.
After few turns of war, Babylon got riflemen. I managed to capture 2 cities on a way to the capital, before their army started returning from the Eastern front to defend their core lands. Luckily, looks like they lost much cavalry in the Incan war, and they didn't have a supply of saltpeter (earlier I was selling saltpeter to them for 50 gpt). But the infantry horde (mostly sonsisting of longbowmen and pikemen) was huge.
Eventually the cavalry stack which got 2 core Babylon cities was blocked. I gathered all of them in one of the cities, leaving the other to the enemy. I was lucky that that city with my garrison did not culture-flip (or, maybe, I had enough cavalry there to prevent culture-flipping totally, as far as I remember, such a number exists).
But their infantry stack did not go to storm the city with my cavalry, they decided to capture the cities in the west instead. This gave me valuable turns to build and bring more reinforcements. Also, after my garrison made a sortie, I've managed to create 2 armies in a turn. In the total during that was I got about 8 armies and lost 2. When things on the frontline were not going well I built a Military Academy in my second capital, but never built a single army there.
Babylon campaign was over. All the rest players stayed in the MA. I still needed some squares to reach domination. So, I decided to attack Arabs, as the biggest faction. I was ready to attack them on the next turn. And decided to force-drive away Arabian units from my territory by "leave or declare war". And they declared war on me! I started the attack, captured 3 cities, but, as my units on the metropoly territory have already moved, I lost 1 my city to the Arabs next turn (that was not an important one). Anyway, I've got domitation victory after 30 hours of play.
Those were great 30 hours
I really like to watch after-game minimap history. Here, I published it on YT with a link access (going to make it public once this COTM is over)
Also, while playing these COTMs I got inspiration to try again to make my own turn-based strategy (which I'm making since 2012 or so). Here's how the newest gameplay looks like: