I finished a game of this going through the tech tree to the Internet. Finished in the 280s which I don't feel too bad about, as the comparable settings at Immortal/Deity have Manpanzee and vadalaz finishing in the 240s with France (which has the chateau and theming bonus unique ability to help them).
Early Game
Settings were low sea level (to expand as much as possible) 3 million years for plenty of hills/mts, temperate arid to have decent shot at desert, salt, and reasonable food production.
Got a coastal capital with a bit of salt but no mountain. There was a salt field to the south and a 3 mining lux city spot not too far away, so I went for it.
The AI civs were on the wonder warpath, so I did not even bother with the early wonders. Great Library is too risky on Immortal anyway and Temple of Artemis is so random you never know. When Stonehenge and Gl went very early, that solidified my call to go expansion with no wonder production.
I went Tradition to buff the capital (which is good for Korea) and max growth/happiness as there were lots of hills but not so many rivers/wheat etc. for food. Figured faithbuying engineers might help for getting the culture wonders late as well.
I got to four cities by the T60s and focused on developing growth/happiness. That 3 lux expansion city was somewhat far, so after national college I got the 5th city up between my cap and the 3 lux city to bridge the gap. There was a nice coastal mountain spot near some cattle/sheep/wheat that could fit a 6th city, so I put that in a bit later. Going wide with Korea is great, and I had the happiness to do it.
So, 6 coastal cities, the two late expansions having mountains while the others did not.
Religion
Got a faith hut early right after T20, so I went Earth Mother and got a religion in the T90s. At immortal it was one of the later religions founded, but i got lucky to have Mosques still available. Nearest 2 City-States were religious, so I got faith from friending/allying them most of the game which helped with this. After 1 missionary, I saved faith for the 2nd great prophet. 2nd follower belief pickings were slim, but chose swords into plowshares to max growth/science in a drive for the internet. Reliquary as the enhancer belief as spreading is a fool's game at Immortal, and there would be plenty of great people to faith buy after completing tradition and aesthetics as planned.
Diplomacy
As for AIs, I maintained friendship or good trading relations at least with the AI civs, Portugal, Germany, Mongolia, Songhai, Carthage, Denmark, Morocco, and Spain.
Sweden was the sticking point that cost me victory speed. Sweden was the closest civ, on the same continent but only near that 3 lux civ up north. Did not get a friendship with Sweden all game for the great person bonus, as Sweden doesn't like expanders, nearby civs, or civs without high military rating overmuch.
After building up some archers to composite bowman early to explore and take out barbarians, I ignored military until Sweden started sniffing around our border and I got intel from Portugal that he was plotting against me. Snuck a hwacha and crossbowman and walls for the northern city into various build queues at that point and those troops with the other missile troops from earlier from early in the game were enough to repel Sweden's first surprise war. It slowed down my build queues midgame then and later. I also had to spend cash upgrading some triremes to turtle ships which didn't help the science/culture effort. At least I got a couple luxes in the peace deal in war 1, which helped a lot at the time!
Later on when I saw the first Carolean around our border, I upgraded the bowmen to gatling guns at great gold cost and built a castle up north. My city defense was in the 60s from tech growth at the time of the 2nd surprise war, so those gatling guns were enough to hold off the Swedish hordes for a few turns until the fortuitous Freedom tenet Volunteer Army gave me 6 free Foreign Legions to turn the tide. Upgraded a few of them into Infantry, also costing valuable money at that point.
The other AI thorn was Spain. I had an early friendship with Isabella, but with a few turns left in the friendship a Great Prophet showed up near the coast. Knowing you cannot control Spanish religious zeal I got proactive. With rapid response from nearby triremes and workers, I kept the prophet away from my shores until the friendship ran out. I did not renew it, then promptly let the prophet onto my land right near an archer (a Spanish missionary also landed the same turn near another city. Luckily, Spain was not allied with other civs (and I was with a few), so my denunciation was later echoed and no ill diplomatic effects occurred by my declaration of war.
Amazingly, the Great prophet had not converted anything yet, so after stealing it i was able to use it to settle a Holy Site! As soon as possible I declared peace to get the Swords into Plowshares back and protect my many coastal trading routes from pillaging. I followed this same formula when the 2nd Great Prophet showed up near my shores, with another holy site gained! The 3rd prophet showed up late game, and I needed to stay good with Isabella for all the Tourism modifier benefits, so I used some ships/workers to keep the prophet from my shores the rest of the game.
Tech
My tech strategy was pottery, archery, mining, animal husbandry, sailing, lux techs, construction (composite bowmen/colosseum needed with 6 cities on Immortal) move toward philosophy (for temples, possible oracle) then Education. After filling in build techs to get workshops started, did Acoustics for the culture stuff and to hit Renaissance Era for Rationalism, then to Printing Press and Scientific Theory. Found last Ai civ the Mongols just a few turns after Printing Press, so no big loss on starting the World Congress.
After Sci Theory, I beelined archaeology to get out a bunch of archaeologists ASAP and then Fertilizer to boost my civ's somewhat stagnating growth before working toward Plastics. It worked out fine, My big 3 production cities (that also got in factories with my 3 coal) built Public Schools quickly while Archaeology was being teched. Then they cranked out a dozen archaeologists while the other cities built public schools. After Plastics, I hard teched to Atomic Theory before bulbing great scientists to hit the Internet a few short turns after Atomic Theory. I ultimately got to Satellites and snuck in Globalization with Oxford too before winning.
I planted my first 2 Great Scientists as academies near my capital, With Korea's bonus for planted great people, it seemed a no brainer. My 3rd one came a bit late, so I held off. I had enough GSes to bulb the Internet once my culture was set and my science was ready.
Gold
1 downside to my approach was that my gold production was not ideal. I had lots of early lux tiles for good early gold, but prioritizing culture/science over gold in general meant banks did not get built until way late. Trade was enough to get me by to buy key buildings or upgrade units as needed, but it meant I never had a huge surplus.
Culture
Pretty simply, I got Writer's guild built a tiny bit on the late side, built the Artist's Guild as soon as possible, and got the Musician's Guild going as soon as was practical given midgame wonder building push. I used every great person to create a great work for the culture/tourism.
There were only 2 culture City states in the world and they were in huge thrall to other civs, so I never got more than friendship with them through quests. I had a free amphitheater and monuments from the Tradition policy. but didn't get the culture buildings going until I got the Aesthetics tenet to boost their production. This was right at the time my archaeologists were out in the wild, so the timing was perfect. Finished museums while archaelogists were digging (though a few archaeologists had to sit and wait a bit)
As for Wonders, I got Sistine Chapel, Globe Theatre, and Leaning Tower of Pisa built by 3 different cities midgame. This helped later Aesthetics policy Flourishing of the Arts granting all 3 cities a 33% culture bonus bonus for having a World wonder.
My big Culture push was winning the World's Fair right when my archaeologists were out digging. Within a few turns after winning the Fair, I finished/bought the last culture buildings, got Hermitage built in the capital, and got the Aesthetics policy Flourishing of the Arts which boosted culture and extended my Golden Age. I was cranking 700+ culture a turn for the rest of the fair, getting me the key Freedom tenets
Creative Expression (small culture help) Volunteer Army (saving resources and possibly my bacon in the 2nd Great Northern War with Sweden) and Media Culture which boosted my tourism a huge amount once broadcast towers got built (still during the fair). It also helped me push down Aesthetics to an eventual finish after the Fair.
World Congress
I established the WC and stayed leader of it through most of the game. It got established a bit on the late side as I went to acoustics before Printing press and had to trireme slog around continents to find Mongolia. The other civs divvied up the city states so no one civ had dominance. I was able to keep 3 or 4 CS allies throughout the game with quests and spies.
First proposal World's Fair was a no-brainer. I needed the culture boost as listed above and it gave me good relations with all the AI civs and allowed several friendships which stayed in force even through ideology changes.
Second proposal International Games was also a no-brainer. Gave me more Ai civ love and got me much needed happiness and 100% tourism for 20 turns which shaved huge numbers of turns off my winning date.
Third proposal Cultural Heritage Sites went through right before victory.
Word to the Wise: At Immortal (or Deity or even Emperor) level, don't screw around with the World's fair or International Games. Drop everything for every city, max production, and go all in on these projects. They will get built quickly on these high levels, so you don't lose too much time in your build queues. If you don't do this, you will likely lose the 1st place trophy (learned the hard way in the past).
Tourism
After getting broadcast towers up and to Media Culture during the World's Fair. I got Aesthetics finisher while building the International Games. I got to the Internet around the same time as the International Games, so during the International Games bonuses I was cranking out 1200-1300+ Tourism with the Ai civs including the modifiers for trade route etc., even with the ones with differing ideologies. I closed a 16000+ gap within 20 turns or so and won in the 280's. Don't forget there is a tourism modifier for having a diplomat in the other civs. I had my spies doing diplomat duty and my cargo ships running trade routes to the 3 or 4 high culture civs as soon as i could.
I faith bought a great artists, a great writer and a great musician to make great works late. I also faith bought three great engineers! 1 for the Statue of liberty, 1 for Sydney Opera House in my capital, and the last for the National Visitor Center for my capital! I got every theming bonus for my museums and wonders.
Conclusion
Anyway, I know that someone who could get Sacred Sites to work, destroy any high culture civs militarily, or make a faster beeline to the Internet with better growth/science could beat this time pretty easily, but I am happy enough. It was an awesome feeling to have the culture buildings, Social Policies, Great People, and Techs come together to explode from 50ish to 1300ish Tourism with the other civs within 20 turns or so near the end.
Good luck to all those giving this a try!
