Difficulty, based on my experiences:
EASY:
*Zulus – Yeah this was simple. No one bothers you , you have almost an entire continent to expand, AND you are connected to most civs by a narrow land bridge. Your power base is unthreatened and you can launch your invasion of mainland EurAsia at your leisure.
*Indians – Surprisingly easy - similar to Zulus, since the Chinese never do anything. Plus you are a little closer to the action. The only problem is you have to deal with the Zulus, but still, this was a first try first time victory for me. No problems.
*Russians – The best part of this is there is no Stalin because YOU are Stalin. Expand in the North and you have a tremendous production base with all those forests. Easy win. Bonus if no Zulus at the start.
*Chinese – Again, you can expand all into the far east and Siberia with no one really bothering you. You do have to move out pretty quick though, as I found out the Zulus will take out everyone and become a pain if you don’t. Good news is once they are dispatched your power base is pretty close to America right across the Pacific.
MEDIUM:
*Mongols – initially harder than I thought. Russians /Babylonians/Egyptians at your doorstep, so you have to take out someone (I went with Babylon) quick to help start a power base. After that is was not quite as hard a game as I thought, but the beginning was somewhat frustrating for sure.
*Americans/Aztec – I went on tech route with Americans and Aztec. Seemed to make sense since you were totally alone after you took out your 1 competitor (except for the occasional new civs in S. America). However these games just dragged on and on.
In the American game the Zulus were of course all powerful so I had to sail an armada with a nuke and take Zimbabwe to halt their progress. After that I used diplomats and nukes to take a lot of cities, since they had somehow gotten conscription and Armor was just not strong enough. Took a long time and my score was crappy cause of all the pollution, even after I tried to clean a lot up.
In the Aztec game I didn’t use Nukes, as the Russians didn’t have gunpowder yet, just went as soon as I had Armor – talk about shock and awe. Just rolled through them like hot knife thru butter. Split them into civil war TWICE. That was a first.
*Romans – easier than French because you don’t have the Russians to deal with, and French/Germans can be dispatched quickly. Once the Greeks are out of the way you can colonize Europe as your power base and go from there.
*Germans – for some reason easier than French, maybe because of better capital placement, and room west to expand. But still hard due to Russians/Greeks/Mongols/Zulus.
*Babylonians – Not as hard as most because THERE ARE NO ZULUS. That means once Egyptians are out of the way (if they are there) you have a whole continent to expand into. I didn’t really need it but it was nice to only have to fight in one direction. Used 2-3 cities from Suez over for my power base, and ended up moving into Europe for the rest, but being centrally located on the map (but not too exposed) allowed me to take out everyone rather quickly. Score would have been better but it was one of the first games I played.
HARD:
*French – I don’t know why this gave me so much difficulty. At first I tried to go occupy Rome with my initial settler, but if I captured it I couldn’t build a capital with a palace. If there was no Rome I had to deal with Stalin and usually the Greeks, which was a tremendous pain, especially when I had limited territory to expand. Eventually the cards fell into place and I had all of Europe to build my power base.
*Greeks – Your placement is terrible. Even if taking out French/Germans, your capital is closer to the angrier civs (Zulus/Mongols/Russians) than you would like. Just getting a small power base established is hard work. The game I won was a drudgery because the Zulus had gotten so strong it was dicey whether I could stand up to them. Thankfully when they fell there was no one that strong in America to contend with.
*Egyptians – typically Zulus are your biggest nightmare. You are their only enemy but you also have everyone else banging on your door from the Suez. My only route was to establish cities in N.Africa and quickly attack Zulus with everything I had from the start. Once that worked I moved on but it is definitely hard at the beginning.
DAMN NEAR IMPOSSIBLE:
*English – My god. You literally have no power base to fall back on. By the time you get to any continent to found/take a city, your enemies already have several useful cities and can knock you out rather quickly. From my experience the only chance I had was to get to N. America ASAP and start founding cities in eastern Canada. If you can knock out Aztec capital quickly you have a shot. Otherwise they will probably overpower you. Using America as a new starting point you can move your capital and expand to build out your power base. Then it’s like any other game. But that first part is very, very difficult.
I posted my victory here:
https://forums.civfanatics.com/threads/emperor-english-earth-my-finest-hour.626587/
Feel free to add your own comments - be curious as to others strategies! Cheers!