First impressions I've noticed is the every AI computer opponent hates you forever the instant you go to war with someone.
Not true, I went to war with two civilizations, and conquered city-state and capitals, and I still managed to repair relationships with civilizations, and by two eras later, I have a mutual friend and a few acquaintances.
AI will forget wars after a while....
First impressions? AI makes very questionable strategic decisions (Washington declares war on me after going on a war craze, but doesn't send an adequate force to destroy me, after it's gone, I have free reign through his territory and then cripple him, doubling my empire).
England navy is verrry powerful, Privateer + 5 Ship of the Lines can conquer any coastal city (no walls, 2 turns, walls, 6 turns), Industrial Era cities.
English extra spy is nice, lets me steal technologies at a faster rate than others.
AI should be building more navy, especially if an enemy is capturing their cities with a navy. Ship of the Line vs. Trireme = one shot. In fact, Washington didn't have Astronomy at that time, so he should prioritize more navy.
Taking cities is incredibly hard now...walls + castle takes about 5 turns of prep + 6 turns of combat to actually take it...even then, you need a lot of reinforcements. This would be nice if Walls and Castle weren't so cheap to build...every city can get them, I'd expect stalemates after a while. Might improve with fighters/bombers, I haven't gotten there yet.
About to hit Modern Era around 1870 AD, Standard Speed, King Difficulty.