These Huge games are such a slog. The Germans got wiped out by the Iroquois/Dutch alliance over 25 turns or so. On turn 1 of the German War, we took their only Oil resource, meaning that we wouldn't see any new Panzers. I had traded the Dutch Synthetic Fibers so that they would also bring Modern Armor to the party. I never did lose any cities to the Germans, as there was a pretty big Dutch buffer between me and the Germans. The Dutch chose to raze a lot of the German cities rather than keep them, although we still had a patchwork of borders. The Germans had built about 4 spaceship parts before the war started, but we knew it would never launch.
Importantly, I took and kept the two German sources of Uranium, meaning that I had 4 Uranium sources while the Dutch had 0. That meant that I could Nuke Dutch cities with impunity at my leisure. Keeping the Dutch close with luxury trades, I was able to build up a force of 26 ICBMs and Tactical Nukes. If the AI was smart, it would understand that when I built an ICBM and re-named it "ICBM The Hague", trouble was on the way. Unfortunately, I lost a source of uranium to random chance and it popped up near Breda, meaning the Dutch in a matter of 5 turns had 7 ICBMs. It was time to attack.
A surprise first strike leveled 25 cities in the Dutch core. Amsterdam had nearly 50 Modern Armor + 6 Mech Infantry in it, meaning that I needed a force of 15 Modern Armor (including an Army) to take it after it was nuked, assuming at least 50% of the Modern Armor were dead, to be safe. The Dutch spaceship, which had been building up since the end of the German war, was destroyed. All 7 Dutch ICBMs were destroyed on the ground in core cities, saving countless Iroquois lives. Wave after wave of Modern Armor follow up the nuke strikes by mopping up remaining troops, leaving slave workers and donut holes of radioactive wasteland. All but 1 of the cities was razed; a too small force of Modern Armor couldn't take one Dutch town. We cut off or pillage every source of Dutch oil in this turn, meaning no new Tanks, Modern Armor, Bombers or the like. They'd be fighting with other kinds of units.
The Dutch army had been cut in half, leaving force numbers about the same as my own. Interturn, the Dutch amassed a force of nearly 70 Modern Armor and Mech Infantry near one of my most product ex-Byzantine cities. Did you notice I built up a force of 26 nukes but only used 25? The last tactical nuke was reserved for follow up; I used it to kill the Stack of Doom just outside the city. The Modern Armor used to raze the Dutch cities was re-assigning to mop up what was left of this force. Another tactical nuke a few turns later reduced a 50+ mech infantry stack into 8 weakened units.
Over the course of wars against 7 other civs, the Dutch and Iroquois had created a very, very long boundary. This boundary was defended largely with barricades thrown up by hundreds of slave workers, defended at key points by draftee Mech Infantry. The cordon defense - famously only useful against smugglers - worked pretty well against the Dutch AI, as their hasty counterrack got re-directed from the Iroquois core. The former lands of the Spanish were poorly defended by the Iroquois on account of a choke point between Iroquois territory and the Dutch core manned by a Dutch mech infantry. Troops and supplies could only move in/out by airport or sea, so we simply didn't spend effort defending them. The Dutch capital jumped to near the Spanish core, meaning that I'll have to likely engage in a real hot war to finish off the Dutch core.
Right now I am cleaning up the remaining cities in striking distance of the Iroquois core, as well as cleaning up the western part of the continent in what was formerly American territory. San Diego was a tactical nuke target, and now Radar and conventional artillery are wiping out the Dutch frontier cities. Once we clean up the west, we will clean up the former Byzantine cities that fell to the Dutch and then move from West Germany through to the (new) Dutch core with some selected additional ICBM strikes. Likely the game will end, as it always does, on a Dutch island south of the former Scandinavia. Unless, of course, I demand the turnover of that city as part of a false peace.
Turns are an hour long or so, endlessly re-positioning defenses and mustering up Modern Armor scattered throughout the wasteland of the former Dutch core. I am not stressing over losing non-core cities for a few turns, as the mech infantry defenders usually can bleed off the Modern Armor that the Dutch can't afford to lose. The Dutch are about to link up an Oil resource that they captured from me in the former Spanish core, so they will be able to build Modern Armor again, but they won't be able to match my production levels. I think they have maybe 50 cities left, spread out across the world and likely very corrupt on distance. I am razing a few per turn at this point, which should accelerate as I can concentrate forces on fewer fronts. We've got an East American front, a West American front, a Northeast Portugal front, a West Byzantine front, an East Byzantine front, a South Byzantine front, a West German front, and a North Iroquois front. Taking out the American fronts and closing out the 4 cities in Portugal to free up troops for elswhere is my curren priority, although the West Byzantine front needs clean up as Dutch and Iroquois cities are too intertwined for my liking.