Spaceship attempt
You are isolated so there are some logistics to sort out to resolve any aggressive actions; how did these go?
We founded Taejon in 690 BC, just before entering the Medieval period, by the gems to have a safe foothold on the continent. From there we started chewing up Chinese towns and founding some new ones. But with just swordsmen and the odd horse, progress was slow and it was not until 300 AD, in a second Chinese war, that we could hurry FP in Beijing. In 400 AD I eliminated China and got a leader to hurry Copernicus.
I failed to settle the four-tile ivory island, occupied by two barb camps - a brilliant touch in this game by the way - before the uprisings around 700 BC, and was unable to find the resources to do so even before the end of the Middle Ages.
Did you find use for your Hwach'a UU?
No, I haven't built any. I have to devote the main part of the shields to city improvements. The Middle Ages is a time when you can earn a lot of money by trading per turn, so I'd much sooner spend shields on horsemen for later upgrades to knigts and cavalries. Artillery units are mainly useful in defensive wars and don't agree well with fast attack units. In the Middle Ages I started attacking civs who have mainly spearman defenders (China, Zululand and USA) I will continue to attack civs who don't have salpeter in the future. Hopefully there will be enough cavalries to attack the fearsome Japanese Samurais. There are useful Japanese towns as close as 5 tiles from Beijing, so this is a must.
As for the Golden Age, I have built Copernicus and will undoubtedly capture Colossus and Great Lighthouse in Zimbabwe, so all I have to do to start my Golden Age is to build one more wonder after the capture of Zimbabwe. This wonder will hopefully be Newton's University in Seoul.
Are any of the AI establishing themselves as a challenge?
It's more a question of finding a research partner and this partner is Persia. I make sure I don't bankrupt them and give them all my luxuries to increase their potential. I also try to remember to renew peace treaties with Persia. The area around Beijing is pretty vulnerable so we don't need hordes of cavalries wrecking it.
As with the Ancient age, I was hoping to make up for my rather poor tech potential by trading techs. This worked fairly well. I don't have time to verify exactly which techs I traded but IIRC it was Engineering, Feudalism, Astronomy, Invention, Chivalry, Gunpowder, Magnetism(3), Printing Press, Navigation, Music Theory, Economics. It was perhaps strange that I researched Military Tradition myself but firstly, I was waiting for Persia to research Magnetism, and secondly I could build few units and so I needed those units to be strong.
We have the fastest tech pace by far now and the main challenge will be to see if/when we can reach the domination limit.
Incomplete Timeline
690 BC - Republic comes in. Only one other civ has it. Naturally, we trade first with Nitwit Japan, owners of The Great Library. Then we get Currency from Zululand. Enter Medieval Age.
Our free tech is Monotheism. Persia's is Engineering and we trade it. We revolt and get 3 turns of anarchy. We do not reroll.
670 - Found town next to gems.
630 - Captured Tsing-Tao, our first captured town.
We are now a republic.
390 - Theology.
350 - Connected gems.
210 - Researched Education and traded Invention.
50 BC - Researched Banking, traded Gunpowder.
90 AD - Traded Chivalry. Researched Chemistry, traded Astronomy.
170 AD - 2nd War on China.
250 - Physics.
300 - First Great Leader # shows up as Beijing is captured.
310 - Hurried FP (safely) in Beijing. War on Mongols - too late to get a large piece of the cake.
320 - ToG.
400 - Eliminated China and got Leader ##2. Leader hurries Copernicus in Beijing. It's too far to Seoul.
440 (ca) - Military Tradition.
460 - Traded Magnetism(3) from Persia. Enter Industrial age. We get Medicine, they get Nationalism.
Check out my pics,
(1) some tax return for playing predator
(2) my modest territory