“…It’s The End of the World As We Know It”
Kefka is the big bad. If that wasn’t obvious by his little tantrum in Thamasa, it’s exceedingly clear once Gestahl starts getting cold feet at the warring triad on the Floating Continent. Kefka’s aims go from “be worshiped as Gods” to “obliterate everything” in a hurry, and Gestahl’s forced to put his rabid dog down.
Unfortunately for him, Kefka knows the rules to this game a bit better than he does.

The statues are moved, and shit. goes. down.
Continents are ruptured, mountains are leveled, and the very structure of the world is permanently changed. It’s all extremely impressive to behold, even on the 16-bit SNES (my favorite part being the horizon shot as the continents begin to separate from each other).
The event changes the nature of the game. The first half has a lot of pain, but a lot of optimism, as well. The second half’s tone becomes one of finding a reason to survive. I actually sort of like the way the idea is presented here.
The thing is, this is sort of the high water mark in terms of actual things happening in the game, which causes a singular problem: It’s all downhill from here. There are still some good moments (we’ve covered a few of them already, and there’s at least one more coming up), but the rest of the game is essentially a “get the band back together and go fight Kefka”.
Now, this isn’t a problem that is unique to Final Fantasy VI, and it never gets to the Chrono Trigger stage, where you can’t remember exactly why you’re so pissed at the final boss. This part does help keep the motivation up for the player, as there’s some actual gameplay/story reasoning on why you want to find Kefka and kick his ass.
It’s definitely an Empire Strikes Back moment. It’s like what…we just failed miserably?
I should also point out the first time I played, I did not save Shadow, because I had no idea he could be saved. I was terrified of letting the clock run down that I jumped off the continent before he showed up. And to be honest, I didn’t miss much except an unsatisfying Relm/Shadow storyline.
the Chrono Trigger stage, where you can’t remember exactly why you’re so pissed at the final boss
Yeah. I remember that it’s Lavos. This is everything I remember about Lavos.
This really is a weird moment. It was fantastic, but as you say, it rips the heart out of the gamer and everything is downhill from here. It’s pretty bleak until after the Kefka fight.