Things are coming down to the wire in my Venice playthrough on King.
I was making a hard push for a science victory, when I noticed two things:
1) Despite his 4th place standing in points, Alexander had gotten a sizable lead in tech, seemingly out of nowhere. My trade routes to him suddenly started returning large amounts of science, and after scouting, I saw that he had machine guns and battleships. I was just getting to Great War infantry, and was still rolling with frigates.
2) He was close to locking up all of the city states, and handily. He got his standing approval with most of them up to just under 300 - a point where even I couldn't buy enough back to make it worth the effort.
So I put my reserves towards upping my navy. Hoarded cash, pushed hard to battleships, moved the entirety of my navy to his most exposed port, and upgraded the lot of 'em in one turn.
He happened to be attacking little ol' Polynesia at the time, and had the bulk of his fleet in one place. I war dec'd by blowing 3/4 of his navy out of the water in a single turn. In fairness, we weren't on great terms...he should have seen it coming.
I've been bombarding him from off-shore for a while now. Since he's still holding sway in the World Congress, nothing will serve but fully eradicating him. Thing is, my happiness is a limiter. I'm one of only two Freedom ideologies on the map (everyone else, Alexander included, is Order) and I'm biting down on about -34 to my happiness as a result (+4 total). So I can't claim all his stuff for myself. Returned Polynesia's capital only for Shaka to take it (fine by me). Gave another to Assyria, and claimed one for myself. Alexander's now allied with every single city state, so I'm at war with 'em all, consequently. They're wreaking havoc on my trade routes. I should have clamped down on this much earlier.
Still, just 4 cities to go. I think I've crippled his economy enough that he can't buy the remaining votes needed for a diplomatic victory, but it was damned close. And now Germany has snuck into the power void, conquering most of Arabia to grab 1st place. But they're heavily invested in a military victory, and I'm not too worried about that.
In retrospect, I'd have balanced myself with more cultural output. I've got too little cultural defense, and no tourist output to speak of, so it's been a constant game of happiness juggling and barbarian spawns at my capital. I could really have used more social policies to help.
But still, so far, so good.