Game was as Japan on PerfectWorld3/Large/Marathon/Immortal
It was so great expirience that I still remember it quite well...
I started between 2 rivers with 2 grain, 1 gem and dozen of silver and forests but no coast in sight.
First turn it was like 90+ turns for first techs. It came down a bit after population was rising but this was game that made me balancing tech costs myself because I only play on marathon and I was sure it wasnt balanced for that.
After finishing exploring my situation was alone on not so small island with one maritime CS and NO coasts to other islands or continents. On whole island there were only 1 gem, around 6-7 silver and 1 more luxury that CS had, also one natural wonder Mt. Fuji (do you see where I'm going?

)
After getting Mining, I beelined to Writing and thx to lots of forests made GL in Kyoto, also since Osaka was on coast also with lots of forests I took risk and managed to build Colossus there.
Since I was very limited in luxuries I stoped at 3 cities and went tall. This helped me a lot getting quite number of SP.
Around year 1500AD I was visited by French and Indian ships and managed to trade my silver for more luxuries, slowly I met more and more civs and got lots of luxuries for my large stockpile of silver. Sad part is that I was dead last as far tech goes...
At year 1600AD thx to lots of new happiness I started fullblown expansion on my island eventually filling it with 15+ cities just to cover the land, and I wasnt trying to make as many cities as possible. Priority was on happiness and science buildings for obvious reasons. Even had to build over 20 workers for all that new land(and considering how long it took them I think it wasnt enough). Thx to full liberty and some tradition policies 2food/hammer walls sped their growth a lot.
With new science boost from lots of new fast growing cities got me Education and soon there was university in almost each city. I also focused capitol 100% on making GS while also producing science with its high production.
Finally I got Astronomy with GS help and started exploring the world. I found out all other civs were on one big continent and they filled it 100% with cities including lots of islands around world. I was lucky to find few tiny islands with luxuries and settled them asap while I could.
Since I was in Renaissance, I started Enlightment SP tree and filled it all but one policy, I was saving its finisher of 2 free techs and also Oxford's 1 free tech for times ahead and used GS while their instant science bonus still mattered.(I think this was only game where I was FORCED to take Enlightment, since in vanilla science is too cheap and goes too fast when compared to historical timeline and thus I almost never took it or even needed it)
Whole purpose of my not so small anymore empire was science. I was trying to get it any way I can eventually getting public schools and with that sealing my position in top 5 with America, Arabia, India and Korea, with rest of world being quite behind. While I was mostly on similiar tech level within top 5, one civ, you can guess it... Korea was around 10-11 techs ahead of rest of us in top5, and that was not all. Korea was also civ with most cities, most gold and strongest military.
Since techs get cheaper if other civs have them, I could see someone was beelining Globalization and since Korea was ONLY one in modern age answer was obvious.
My chances of any victory type were impossible. And if Korea builds UN its probably game over!
My only chance of stopping Korea and then maybe win was military intervention followed by worldwide conquest. Using my free techs I beelined to modern age getting research labs. Thx to labs I got my science to over 5k per turn and started backtracking to research military side of tech tree so I can get major advantage that my opponent does not have... Battleships!
Around year 1980 Seoul started building UN, and I had to start war with what I had. Limited to fleet of 4 battleships, 2 carriers filled with fighters and lots of submarines. And army of 1 tank, few infantry and lots of light infantry. Their coast where also Seoul was located was full of destroyers. When I approached them I was in for a nasty suprise. They had more submarines than I anticipated, even more than destroyers.
Thanks to both my units with superior promotions and not so great AI I managed to destory their fleet around their capitol while losing quite number of my subs in process.
My carriers full with fighters also saved me from their trys to sink my battleships with their airforce. Their capitol was surrounded with huge army including lots of artillery so my ships couldnt come too close. And my land forces were both weaker and smaller numbers. Eventually along their coast I found weakly defended territory and managed to make beachhead. Slowly moving along coast at both land and sea I was capturing cities including 50+pop Seoul and around 15+ wonders it had. Even then when my score skyrocketed Korea still had bigger score

. Because of constant losses and building of new troops eventually I ended with huge army costing around 800gold per turn while having Nationalism lower maintance costs.
All that was left was long conquest of rest of world that now I had capability to do. Tired of huge time consuming logistics and AI turns lasting 5-10mins that was end for me.
I already had my hard and fulfilling victory