The game itself. The most iconic Final Fantasy characters ever, including: Cecil, Terra, Cloud, Garland, Kefka, Sephiroth, and many more, in a battle to decide the fate of all Final Fantasies. That means this game has the highest stakes of all.
Just the above scene. The Warrior of Light slowly ascendng to Chaos's throne while badass music plays and we see the other heroes in turn, each one focused and ready to take Chaos down. The Warrior finally reaches the peak and Chaos, undaunted by the ten heroes, goes on to challenge them all. All done to badass music.
Gilgamesh, as he does in so many other ways, barely fails at beating Chaos to a Title Drop with his "Ultimate Illusion".
The intro emphasizes pretty well the ridiculous extremes to which the Rule of Cool is taken for this game to exist. It is a five-minute long Square-animated CG FMV sequence of the twenty combatants in one gigantic battle royale that includes, among other such moments, Squall squaring off with Sephiroth while running up a glacier, Zidane and Kefka clashing in midair, the Light Warrior, the Onion Knight, Cecil, and Cloud all ganging up on Garland, Tidus and Zidane pulling a Fastball Special against Exdeath, Terra and Ultimecia having a long-range magic duel, Firion swinging through the air on a grappling-hook-knife-thing after being knocked off the platform by Jecht... the list goes on and on. Perhaps the greatest thing is that practically all of these physics-defying extravagances are actually more or less achievable in the gameplay itself, subverting Cutscene Power to the Max for the first time in a Square game in a long time.
The Fastball Special Tidus and Zidane pull off? Both of them are in midair. Tidus jumps into the air just fast enough for Zidane to wrap his tail around Tidus' ankle so Tidus can essentially kick him at Exdeath. Now that is an Indy Ploy.
Squall and Zidane's Destiny Odyssey modes provide a twofer: Squall goes to confront Ultimecia alone, and when she congratulates him for being heartless and selfish enough to abandon the other heroes, proves her wrong with a "World of Cardboard" Speech declaring his belief in the Power of Trust and the Power of Friendship. He announces his willingness to take on both Ultimecia and Garland by himself to make the others' lives easier, preparing to fight both of them at once...
Honestly, that entire speech by Squall, I could see what was going to happen (that someone would show up and help; I just had no idea who), and it didn't detract from the sheer awesomeness of the scene AT ALL.
Squall: It's because of them that I can't allow myself to stop. (summons out his Gunblade) I know that I'm not alone. That's why I can fight by myself!
Ultimecia: Interesting... Then fight you shall.
Garland: Haha. Yes, against the two of us.
Ultimecia: Will you still feign bravery?
Squall: This is better for me. If I can defeat both of you, then it will make it easier for them. I'll prove it to you. We may be apart, but we still fight together!
The funny part about this is that both Zidane and Squall have the same reactions to each other from their own points of view, "That idiot!"
The Ex-Bursts alone are worth mentioning; all of them do something truly badass. Whether it be a simulation of their Limit Break from their respective game for most of them, Jecht almost parodying his own son's by doing the same things he does with a Blitzball with a meteor, the Cloud of Darkness laser-beaming the target into oblivion, Onion Knight reducing the fighting game momentarily into menus... Particularly Bartz using almost ALL of his allies' weapons in his Game Breaker setup from the game that he came from, and Exdeath using the power of the Void to crush the target with his bare hands.
Before the final battle in every Destiny Odyssey, the villain-hero pair each get these. Examples include:
The Emperor traps Firion and conjures a ring of energy orbs that explode and seem to knock him out. Firion's weapons float up from his limp form and fly forward, almost impaling the Emperor. Firion then gets up and calls his weapons back, holding his sword in front of his face ready to fight, and proclaiming that as long as he is alive, he will never give up.
Also, following the Emperor's defeat in the Shade Impulse, he asks what on earth Firion is. Firion's reply? "Just a swarm of insects."
Of course, Cecil, Bartz, and Cloud have their own echoes for him, too, but Firion's just stands out as most awesome.
Terra faces off with Kefka while her friends hold off the Cloud of Darkness. Kefka proceeds to unleash a metric fuckton of explosive spells at her. Terra responds by running the fuck away, culminating in using a Teleport spell to escape when she can't run anymore. Kefka appears directly behind her in a capsule and shatters the glass, Force Repulse style.
As Squall attacks her, Ultimecia freezes time, moves out of the way, surrounds Squall in a flurry of magic bolts, then unfreezes time to bombard him. Squall survives and declares he doesn't care if she controls time — he still plans to beat her.
This one is especially awesome, as it's a Crowning Moment for BOTH the hero and villain. Ultimecia pulls an awesome move, basically using her Ex-Burst on him, only to have Squall block the entire thing, unlike Onion Knight and Firion, who got smacked down in what should have been a KO (of course, given the battle system, what is and isn't a KO is constantly in flux; maybe they didn't have enough Brave points.)
Tidus attacks Jecht, but Jecht shrugs it off and knocks Tidus half-way across the arena with one punch. He then goes over, lectures him on how he never stood a chance, and then starts to leave. Tidus slowly gets to his feet and calls Jecht back to keep fighting.
Tidus: "Where are you going? There's no tomorrow for me... UNLESS I BEAT YOU TODAY!"
On top of that, this is the only time Tidus and Jecht get to fight one another, man-to-man. In Final Fantasy X, Jecht and Tidus never really got to cross swords, so this is a beautifulWhat If? scenario.
How about the Onion Knight trying to get in a crowning moment, only to have the Cloud Of Darkness completely shut it down and have one of her own instead, shooting him in the face with her Particle Beam after making him look completely out of his league?
Pretty much any time the characters quote or paraphrase themselves from their original game is bound to get at least one fan squealing. And of course, half the dialogue in the game parallels, paraphrases, or directly quotes the original series.
Even better, he manages to be one of the few to actually give a satisfying response to the villain's last words.
"I couldn't stand a day without a past or future. I need to live each moment — to keep fighting here and now."
For many, if not all, of the characters right before the battles from which they obtain the crystals, and afterwards as well.
Particularly Squall, to the point Zidane had to pull off his own CMoA to tell him he was showing off too much!
Warrior of Light's is a beautiful hero moment: to Garland, upon vowing to end the eternal cycle of fighting and death they're locked in — "Whatever destiny the world may hold for me, I will never give up. This battle shall come to an end, and I shall save you too!"
There isn't a fanboy/girl who didn't squeal when Bartz dual-wielded Cloud's Buster Sword and Squall's Gunblade before attacking Exdeath.
For the player: Beating Chaos in Inward Chaos.
Just before that, seeing all ten Warriors of Cosmos lined up to fight Chaos, with cuts to each one from Tidus to the Warrior of Light walking up the steps. That is epic, that is awesome, that is exactly what this game is about.
How about beating Feral Chaos in Dissidia 012?
Though you probably went Oh Crap when you first saw it, it's hard to deny that Utter Chaos may be one of the coolest attacks in the series. Goes double for Regnum Dei.
This could also double as a crowning moment of funny. But when Terra ends up getting Kefka to say "sorry ma'am" is fricking awesome!
In 012 Duodecim, while the other six remaining Warriors of Cosmos set out on their mission to stop the influx of manikins, the Warrior of Light stays with Cosmos as her last line of defense... and faces down the manikin horde, fully prepared to go down fighting to keep them away from Cosmos and take as many with him as he can. He faces at least as many manikins as the other six warriors do, and he holds out just as long.
And then, at the end, when he finally runs out of strength, Cosmos comes to HIS aid. After a game and a half of seeing her do nothing but sit on her throne, silently expending her powers to counter Chaos's, we see what happens when she abandons that position. She rises from her throne, and defends the Warrior of Light with a radiant shield that annihilates the entire Manikin horde. The effort causes her own death, but we finally get to see what she would be capable of were she not under constant assault from the power of discord.
Speaking of which: Lightning, Vaan, Yuna, Laguna, Tifa, and Kain's headlong assault on the source of the manikins, complete with a battle royale versus Garland, Kefka, Emperor, Cloud of Darkness, and Ultimecia, a You Shall Not Pass by Kain, and ultimately a group Heroic Sacrifice to close the rift so that the other Warriors would not be overrun with manikins in the next cycle, is also pretty awesome.
The above undermines Kain's contribution. He has been going around for who knows how long, trying to prevent his friends from being permanently erased by the manikins by offing them himself. He then has to face Exdeath, and then a pack of manikins assuming his own form. He then saves Tifa from Ultimecia. He's somewhat reinvigorated by a Potion Tifa was carrying, but then has to face both Exdeath and Golbez (well, mostly Exdeath, seeing as Golbez was pulling his Stealth Mentor shtick as usual) as he tells the group to go on ahead and stop the influx of manikins. After he's done, Kain is shown to be weary and battered from the fight. And he tells Golbez that he's still adamant on facing what is certain death against the manikins, earning the thanks of Golbez for saving his brother Cecil. He then drags his broken body and catches up to his allies just in time to face the manikins, and fightsto the bitter endagainst his foes alongside the others. And he charges into the fray. Not a light jog like the others; he goes into a sprinting crouch start position and takes off in a blur of wind. He's shown to be the third-to-last to finally go down (after Vaan, and before Tifa and Lightning). As said above, this prevents the manikins from overrunning the next cycle. Truly theDeterminator to end all Determinators.
Exdeath: "So, you offer your life in exchange for theirs?"
Kain: "Of course not. I offer yours".
Cloud in Duodecim. Back in the 12th cycle when he was a Warrior of Chaos, he saved Tifa from Sephiroth. After already having doubts about his role in the conflict, meeting Tifa makes him realize he's fighting for the wrong side. So he goes to talk to Cosmos, right? Nope. He goes and picks a fight with Chaos. It didn't end well for him, but he has brass balls to try.
Chaos himself did pretty well here. Statistically, he's merely at level one, so you expect a quick victory, right? Wrong. He's just as fast and deadly as in the original's final battle (which is very bad, given Cloud's Mighty Glacier tendencies). When Cloud "wins"? Chaos laughs it off, insults Cloud's strength, and proceeds to frag him with a giant energy beam. He then gives the dying Cloud a brutal "The Reason You Suck" Speech that doubles as a Badass Boast; telling him that he and his "vaunted blade" have changed nothing and that all he has accomplished, and all he can ever hope to accomplish, is hastening his own destruction. This proves that, before finally losing his drive in Shade Impulse, Chaos was not one to be fucked with.
Thus it becomes ever so delicious to beat his ass with Cloud in Shade Impulse.
Yuna is Martial Pacifist in trying to peacefully resolve the conflict between Brainwashed and Crazy Tidus and Jecht, but when The Emperor shoots him, she doesn't ask questions, plead, or let her guardian take care of it. She just beats the crap out of him. Twice. So simple, but so elegantly awesome.
In Scenario 000, once you start to close in on Feral Chaos, the BGM suddenly shifts to "Canto Mortis", which replaces every other BGM track for the Scenario's previous areas. If there was ever a theme that said "shit just got real", its this one.