I've started a new campaign some days ago, it had been a long time since my last one. I play my own heavily modded version, but it's mainly focused on units' statistics, some tech rework (imho the tech tree is the weakest part of the game), and some cultural rework. Nothing big.
Anyway, I play on medium maps with several continents, 30% landmass, continents evenly spread out.
I started as Harappans on a small continent with a single Egyptian neighbor, which started friendly but since I wasn't having much luck with encounters was starting to advance faster than me (first city a couple turns before me, Pyramids all over the place, etc). So obviously I decided to go hard on military and crush him before he could bury me. The war was relatively easy, if long. With the entire continent for myself, I focused on growth and territorial gains. I was slow with the naval tech because of how few scientists I had and how much time I spent beelining siege and army technologies.
I was already seeing other cultures' Pentekonteres sailing around my continent, but I finally managed to colonize a big island (around 1/5 of my continent) and ransack and recolonize another big island nearby. As I discovered, those two islands were between my own continent and a much bigger one.
That continent was split mainly between the aggressive William Wallace leading the Olmecs, and Shaka Zulu leading the Nubians. I thought they'd keep themselves locked in some struggle, but I realized at some point Wallace vassallized Shaka Zulu (HOW??? They were the same size).
Being both very aggressive, they both laid claim to my islands, and I tried to resist. Bad idea: both of them were much more advanced and fielded military units of at least a "level" beyond mine. I tried using Spearmen and Swordsmen against Gothic Cavalrymen and it went as well as you could imagine. Their QUadriremes crushed my Pentekonteres.
Initially they only wanted a territory and not my colonial city, but every time I tried to offer them the land they refused. I adopted the Roman culture and used Legions and Quadriremes to fight them off, but I was still constantly on the backfoot. Rome (renamed the colonial city) fell and languished under Gothic occupation for decades at the time. Gothic armies routinely invaded my continent and were barely beaten back at the walls of my cities. It was truly the Barbaric Invasions for all the Classical and Medieval eras.
Finally, slowly, I managed to turn the tide by tortorously maneuvering to concentrate my armies and navies against one stack at the time, and managed to wear them down to a white peace. From then on, my country has switched priorities so thoroughly that every single decision has been focused toward not letting the invasions happen again, and keeping Rome safe. I pivoted hard into naval tech and military, emptied my massive cities to levy troops, and cannibalized weaker cultures far away to build a "reserve". The Early Modern era was the first one when I wasn't always on the backfoot.
The campaign went on, I got invaded and lost Rome more times, but slowly managed to turn the tide and finally obtain military superiority. I'm now in the early Industrial Era and I'm now on top and invading THEIR continent.
The AI's aggressiveness pulled me from the expected "long, semi-peaceful game" I tried early on and forced me to be shrewd and militarist. I especially enjoyed being hard pressed by a competent opponent instead of steamrolling.
This game is still so good!
