Interesting game. I did okay but there are definitely still areas for improvement.
[CITY PLACEMENT]
I wanted a coastal capital. Didn't notice the barely visible shoreline to the north and east, so I instead went southwest. After my warrior revealed a second crab and some cows, I settled Amsterdam (on Turn 2) on the coastal hill. It took me awhile to settle my second city because I wanted to build NC first. Settled Rotterdam on the desert area to the east near all the crabs. Had just 2 cities until mid-game, when I finally settled a third (Utrecht) near the Grand Mesa between Mombasa and Sidon. Fourth city (Groningen) was in the hilly region to the west. In the end game I made the mistake of settling 5th and 6th cities near Krakatoa and GBR. I had wanted to settle a third city near the initial start area (near the stones and iron) but never got around to it.
My capital choice was good for God of the Seas, but it did take a long while to get a Pantheon. Settling on turn 2 with not much production set me behind. If you are slow getting a Pantheon, you can get really delayed since each pantheon founded will delay you for an additional 5 turns (if relying on a shrine). I was the 5th to get a pantheon. In contrast, settling in place on Turn 0 would net you 2 extra turns, and you'd have an extra hammer (from the stone grassland) to build the shrine faster.
Rotterdam was good. And Utrecht (on the Dyes near Grand Mesa but I never actually got the Mesa which was in the third ring) was helpful due to the luxes and jungle. Groningen in the hills was probably a mistake. I wanted Machu Picchu (wasn't that helpful) and Neuschwanstein (didn't have time to build) as well as an Observatory (which wasn't that great). Instead, I should have settled my third city near my first two (to get 2 stone, iron, and another crab) and then my fourth city should have been near the Grand Mesa.
Having my cities so spread apart meant that my third and fourth couldn't really contribute to spaceship parts. Even if I built them, it would take too long to reach my capital. I also should have stuck to just 4 cities. I went with Tradition (not Liberty) and was culturally deficient for most of the game. I don't think the 5th and 6th cities contributed much. If anything, they prevented me from getting some useful National Wonders like Ironworks, Hermitage, and National Treasury.
[SOCIAL POLICIES]
Went full Tradition (I love me some wonders). Had another policy before Renaissance, so I opened up Commerce. I considered Patronage but decided I wouldn't have the gold to ally many CS' and I really wanted to eventually get Merchant Navy (all my cities coastal so +3 hammers would be great) but never had the SP's to get any deeper in Commerce. Then I did Rationalism up until Scientific Revolution (RA's). I opened Order wanting to get Planned Economy but there wasn't really any time before I had to just finish up Rationalism instead.
I was fine with my SP choices and would do them again. However, I was culturally deficient for most of the game. Settling 5th and 6th cities was a mistake. And I should have been better about building amphitheaters and opera houses in my cities. There was just never any time or money!
[RELIGION]
Due to my late settlement, I was 5th to found a Pantheon but did get God of the Sea.
Was third to get a religion. I wanted to have fun so I chose Interfaith Dialogue and Divine Inspiration. Second to enhance, with Religious Community and Holy Order (cheaper missionaries).
Since religion was so popular in this game, I wanted to get a science boost by sending out lots of missionaries with Interfaith Dialogue. It was interesting, but in hindsight I think I would have been better off with a gold founder belief (Tithe, Church Property) instead and the ever reliable Itinerent Preachers or Religious Texts. But hey, I wanted something different.
Three of the religions were on the other continent, so only the Celts had a religion near me. I wondered whether I should let other religions take hold on my continent so I could benefit from Interfaith Dialogue, but decided that the diplomatic bonuses with major AI's and the CS benefits outweighed waiting. Spent one missionary to convert my cities, one each to Russia, Spain, and France. One had a dialogue with the Celtic Confucianists, and three went overseas (one talking with English Buddhists and two with Roman Christians). Stopped buying missionaries after Industrial began. I eventually bought 2 Scientists and 2 Engineers with my late game faith.
I thought God of the Sea + Divine Inspiration + Religious Community worked well.
Due to my peaceful game, I think it would have been interesting to try Fertility Rites + Swords into Plowshares instead.
[DIPLOMACY]
I played a very peaceful game. Was never in a single war. Besides my initial warrior, I built one scout and bought an archer. Every other military unit was gifted from CS (I ended up about 4th in Military).
Catherine was very quick to befriend me. Both Isabella and Napoleon were mad at me for awhile (Isabella was even Hostile) due to my wonder whoring, but I eventually won them over as well as Boudicca.
On the other continent, both Elizabeth and Gustavus were eager to befriend me, but Augustus was aloof and indifferent for a long time until I was able to thaw his icy disposition and become friends with him too.
So I was able to then maintain constant friendships with all 7 of the other civs (which is actually a bit challenging since you lose out on the easy shared Denouncement and shared War modifiers).
I signed a total of 13 Research Agreements in the game. 2 each with each of 6 civs, though only 1 with Rome since it took awhile for our friendship to blossom.
Maybe I should have signed RA's as soon as I researched Education, but I waited a while for Scientific Revolution + Porcelain Tower. I really didn't need that last RA though.
I did play peacekeeper a lot. France DoW'ed Almaty early on and I covertly helped protect Almaty. Later France DoW'ed the Celts and eventually Russia and once again, I helped peacefully impede the French forces. In fact, France would have steamrolled Russia without my involvement - I single handedly saved her capital. On the other continent, England was hammering both Ragusa and Sweden. I helped protect Ragusa for a while, but eventually let it fall to focus on Sweden. Helped delay the English invasion for quite some time but eventually coughed up about 765 gold to England so that she would declare peace with Gustavus.
In the early game, Catherine and Boudicca went Honor, Napoleon went Liberty, and Isabella went Tradition. With G&K, I've found that early Liberty civs do A LOT better than everyone else. Tradition civs do okay, but most of the time early Honor civs do extremely poorly. They stick to just one or two cities and have a massive early army but they rarely take advantage of it and don't upgrade it well.
Maybe I should have DoW'ed a CS early on to steal a worker, but I really didn't want the negative warmonger modifiers.
I feel like the optimal finishing time probably *does* involve taking out a couple of civs to increase your own research base and then RA'ing with a few civs from the other continent. So I probably would have been faster if I attacked one or two civs but that's not my preferred style.
[WONDERS]
Beelined for GL, NC, and then SH.
After that, it was keep away, to beat Spain, France, the Celts, and Russia from other wonders. Built Great Lighthouse, Pyramids, and Colossus which normally aren't that great but were in my case. The free lighthouse and +1 gold for water tiles were amazing for my capital and all the crab meat. The workers from the Pyramids were helpful for later Polder building. Then built HG and Terracotta to beat the others civs.
After that I wasted time on the Great Wall which I really shouldn't have. I had my second and fourth cities build Petra and Machu Picchu but neither of them were that helpful either. Later on I also built Forbidden Palace, Notre Dame, Alhambra, Angkor Wat, Sistine Chapel, and Himeji Castle in order to deny them to other civs but maybe I shouldn't have bothered. Didn't really need the happiness from Forbidden Palace or ND. My culture was crappy with or without Alhambra and Sistine Chapel. I bought a lot of tiles but Angkor Wat probably wasn't worth it. And since I was never in a war, both GW and Himeji were useless. Wish I could have gotten a refund.
Near the end game, I did resist the urge to beat the Celts to the Kremlin (another useless wonder) so for once, I actually let them have it.
I could have timed Taj Mahal better. I did get a lot of mileage out of Big Ben and wish I had built it earlier. At the end of the game, I used Engineers to rush Statue of Liberty, Hubble Telescope, CN Tower, and Sydney Opera House.
[MISC]
Since I was peaceful (built 1 Scout and bought 1 Archer), I had no use for the Sea Beggar.
I did have fun with Polders. Researched Guilds only after Education and Astronomy, so I was a bit late. But they are quite a good investment after Economics. As mentioned, I would really love to replay with a Tradition + Fertility Rites + Swords into Plowshores build (too bad no DLC or you could add ToA in as well). It was a little annoying to discover Oil underneath Polders after Biology. Converting it into an oil well means that you first have to clear the marsh, so the tile is unproductive while building the oil well. So I just saw the oil as +1 production and kept it as a polder.
My end game was a bit messy. I didn't need my final (13th) Research Agreement. Or I didn't really need all my stockpiled (3) Great Scientists. In addition, I forgot about the "one tech/turn" limit which applies to Great Scientists. So I lost a few turns there. In addition, I had to wait a turn to get enough faith for my final Engineer (for Sydney Opera House) so that set me back a single turn as well. If I replayed the final turns, I'm sure I could have shaved a few turns off of my finishing time.