First of all, as an aside, I noticed in my final sessions that I killed more
barb units than Gandhi's units. Even some random savages in loincloths, it turns out, put up a better fight than the supposed strongest runaway AI in this game...from a certain point of view.
That being said, we were considering going nukes but what really sealed the deal was Mansa having already gone fission.
He was teching like a champ with just a few crappy cities, but without enough production to make much military, all good things must come to an end...
Despite having bribed Hatty on me, Mansa caps after
one turn of war and me taking Timbuktu (+1 other city that was being annoying culturally)! Truly the biggest wuss I've ever seen, though with less than 12 land tiles on the mainland and a few crappy island cities, it's not like he could've fought back more. His navy was also conveniently blasted when I bribed him on Gandhi and Gandhi subsequently destroyed his frigates with destroyers. Then 2 turns later Hatty uses AP to make peace with everyone...she wouldn't have been a threat anyways, as I was 80% her power at this point with only relatively few arties + cavs + rifles running around, and Gandhi with his shiny tanks was a sufficient meatshield.
Afterwards I traded smartly to quickly catch up. I used my strategy of ping-ponging between the two vassals at this point. I gave artillery to Gandhi for part of AL, rocketry to Gandhi for a part of electricity (IIRC), rocketry to Mansa for part of fission, fission to Gandhi for part of industrialism, and then industrialism back to Mansa for railroad! But even on our way to nukes and not having reached them, though, the fun didn't end there. Lincoln for some reason went medicine and radio before rifling and assembly line (or even steam power...sure...). He got rifles and then infantry in a trade when I landed my now respectable stack, but it was too late, so all I had to do to cap him was kill pretty much 3 infantry and a bunch of medieval crap. It didn't help that Lizzy declared on Pacal a few turns prior and bribed him in, so his entire army (probably 10 cuirassiers or something dumb) was roaming Pacal's lands. After I capped him I got a pretty sick trade...almost was tempted to go space at this point, as you all know is my nature

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Speaking of Pacal...poor bastard was 2 eras behind. Despite having a gold and corn start, which I think
@Gwaja may have edited or hand-picked to make him OP...his extremely low comparative peaceweight and isolated religion made him a pariah. Being the worst enemy of 3 people (later 4, as Hatty was bribed in into the war) doesn't do good things for your tech pace...regardless of how financial you are. He also decided to go culture
before rifling...probably because he realized he had no chance in **** of winning space? Somewhat smart, except that meant I could also murder his medieval crap with impunity. When you made this map, I don't think you expected me to use arties + infantry vs longbows and cuirassiers against multiple AIs

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Finally it was time to move to the big boys (or, well, girls). Around this time I traded fission and completed Manhattan projected, and queued ICBMs/tactical nukes in every city. I got flight and industrialism to mass-airlift Panzers which really sealed everyone's fate, but...at this point, that was more of a formality. After nuking every single city and stack 2-3 times, there was no resistance against even my unupgraded rifles, much less my now-veteran core army of arties and battle-hardened infantry. My woodsman-medic had now became an ubermedic with the full +40% healing/turn promos, while I also think I got a CRIII axe from all the way against JC to become a nutcracker infantry for the paltry resistance in the irradiated wastelands I had left behind (my great general units were named General Iroh, Medic TF2, and Raiden...I think fitting for 2 healers and a dude who started out as someone who chopped people into pieces with a large and sharp implement, if you get the references). I used ships to nuke and capture London and 1 other city in the first turn of the war against Lizzy; she gave in after 2 more rounds of nukings + captures. I used similar naval tactics to strike against Hatty, and she too gave in after 4 cities were taken. I even got some mobile artillery at the end, purely for style points because it really wasn't even necessary. At the last turn, Hatty finally amassed some tactical nukes...so I nuked her nukes and took the cities that contained them, crushing the last resistance to my reign of terror

. And thus, on t239, 1645AD, a mere 40 turns after I had just capped my first AI, I won conquest - and world peace was achieved with a worldwide nuclear cleansing

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(Pictures continued in next post because of attachment limit).