FFX is my go to example for "twist can work but the writer need to put in the work to make it work". The great thing about the twist is that its properly setup but its not in your face about it at all, there's a ton of little awkward moment like when Titus talk about how they should totally come back to some area after they kill Sin and everyone stays awkwardly silent. But on first playtrough you don't really notice it because Titus is kinda awkard as a character. This is a bit of a double edge sword, because while it really help makes the story and twists much better, it makes Titus not that likable as a character. But here the game has a secret weapon, Yuna is a wonderful main character who can carry the game without issue. And so the two work really well together. And while I wouldn't hang out with Titus as a person, I do like his character arc. He's so angry at everyone when he find out that Yuna will die if they kill Sin. Yet later on when he's told he'll die if they really kill Sin, he doesn't tell anyone about it, not even Yuna. There's a lot of nice little touch in Titus story that makes it great to see him evolve, I wish Squall has receive even 1/10 of that character development. Speaking of first game to have voice acting, the game let you name Titus, so because of that nobody ever mention his name in the entire game, its kinda awkward...
The story biggest weakness is it lack of a good antagonist, Sin is more like a natural disaster to really work. Yu Yevon isn't introduce until way late in the story. And then there's Seymour, the game cleverly let you control him for a boss fight early in the game, where he can easily wipe the floor with the boss. But then 5 hours later you kill the dude and its hard to take him seriously after that... To compensate that the game give him the toughest boss fight of the game, but its pretty gimmicky and mostly annoying because if you die you have to watch the same cut scene over and over again. Also the game made him look super fucking evil and always play this evil theme whenever he shows up, which makes it really hard to act surprised when he turn out evil. A bit of subtlety would have gone a long way here.
Gameplay wise I quite like the turn base system and being able to switch character on the fly, it also gives a fun little challenge where I usually try to use every character in every fight. The summon are great in combat, which is nice considering summoning is such a big part of the story. Only issue is the game is overall too easy outside of a few select fight. Also a lot of character severely fall back as the game progress, magic is almost entirely worthless in end game and summoner don't tend to work anymore in tough fight. Combine that with the fact that there's a couple of fight you have to do with the character who can swim (only 3 of them) and it usually means you'll only use those three character for all of the end game.
The sphere grid is a good idea, poorly executed. In theory its a really cool way of letting you customize your character, think of every path as a "class" and by letting the character cross over into other character path you have a very nice system to let player multi class. Plus you could have split path, which would make really nice "sub class". But the game doesn't do any of that, its just a linear path, there's also no passive ability on the sphere grid, limiting how interesting the path are. Once you finish the path you have a little part of the game where its actually interesting and you can have your character go down other character path, except that at that time you get a bunch of item that let you teleport anywhere on the grid, and so you just grab a few import abilities and then gather every at the same location and just use item that let you change the node to stats+4 node. It's pretty disappointing. I wished they tried the system one more time and improved on it, but they never did sadly.
I won't get into all the mini game, some are good, some are bad and some are ugly. Blitzball is pretty massive and has the potential to be interesting, but stats are way too big of a factor and pretty quickly you can score goal the moment a character touch the ball no matter where they are. Credit where credit due, the game keeps saying Titus is a blitzball star and its not fucking kidding, you literally start with the best character in blitzball and he can easily carry you to victory. With just a few tweaks blitzball could have been great, but it just miss the goal. As a fun side aspect the game let you recruit a bunch of player into your team, including all the opponent, and all the other team will also change player once in awhile, it pretty fun to see the weird combination the game will come up. Like the Al Bhed team having no Al Bhed in them (I didn't touch on Al Bhed in story but suffice to say, if you want the player to feel symphathetic toward a minority, maybe don't make them massive asshole the entire game).
I didn't mention music in any of my post cause pretty much all of them have excellent soundtrack and it gets repetitive, but FFX is probably my favorite of them all. It has amazing range and is just perfect to highlight certain scene mood.
So I talked about 2 aspects in FFX that where very close to working really well but didn't quite. Shame FF don't do direct sequel, would have been the perfect occasion to polish those system. Wait, what's that? There's a direct FFX sequel! Omg I can't wait to see how... Oh no!!