Also doubles as a Crowning Moment of Heartwarming, but the scene where the party gathers together to fight Bahamut SIN, reunited again, and all help Cloud to reach the ascended enemy by taking turns helping him fly... including the lost 9th member of the team.
Before that, when Tifa tries to fight off some of the hellhounds attacking Denzel, and dodges a shot from Bahamut, which blows up a building, that's about to collapse on her, while Denzel is facing a horde of hellhounds... And Cloud comes in for a truly epic Big Damn Heroes moment as he throws his sword like a boomerang which destroys all the hellhounds, and hacks his way through a gauntlet of building debris to save Tifa.
Also a bit heartwarming just moments before it all happens, we see both scenarios spliced with two traumatic moments from the past: The death of Aeris who got killed from above, and the fall of Zack who faced an unbeatable army. Cloud sees them in conjunction with the situations of his adoptive son and childhood friend... And he sure as hell ain't letting it happen again.
Vincent has the best line when doing his part: "Fly."
Arguably the fight that takes the proverbial cake is the one with Bahamut Sin when he◊ started laying the smack down (yes, I did just say that; it's Bahamut), then the remixed boss battle music started, et cetera.
Can you say... Omnislash? Cloud lands, several of his swords land around him (point first, obviously), and he catches the last one, with a look like "I win."
In CompleteCloud hits Sephiroth with the original Omnislash. Whilst this is what defeated him in the game, this time Sephiroth just blocks all of Cloud's strikes and impales Cloud in response during the final blow, then throws him into the air and hits Cloud with an Octaslash, slams him into the ground and does the "Tell me what you cherish most" speech, then time seems to freeze as Zack shows up to provide moral support to Cloud.
Zack: So what if it looks hopeless? If it was me, I still wouldn't give up. Embrace your dreams, and no matter what happens, protect your honor as SOLDIER. Well, ok, you never made SOLDIER, but it's what's in here [Puts fist over heart] that counts. Cloud: Zack... Zack: So, need any help? Cloud: No. [Cloud starts to stand up and shakes his head "no"] Zack: You already beat him once didn't you? This should be a cinch! Cloud: Yeah. Zack: Cloud, you know what I told you. Cloud: That's right, I am your living legacy.
Then from here, Cloud attacks Sephiroth and draws him into the air and unleashes Omnislash Ver. 5 and finishes Sephiroth off.
Another awesome moment happens right after.Sephiroth has Cloud at his mercy after their spectacular final battle, and asks Cloud what is that he cherishes most, so he can have the pleasure of taking it away from him. This cause Cloud to have a brief flashback to all his loved ones, present and lost, giving him the strength to pull the Masamune out of his shoulder and take Sephiroth down with his new Omnislash. The look on the One Winged Angel's face was truly, truly priceless.
Rude & Reno fighting off Loz & Yazoo. Especially when you factor in Yazoo & Loz essentially being mini-Sephiroths. That two normal dudes actually managed to hold them off, makes their fight impressive, despite their loss.
Reno: Forget your little "Reunion" and GET A GRIP!
The entire final fight scene. The number of buildings that get sliced in half through sheer force of awesome is… impressive.
"I pity you. You just don't get it… there isn't a thing I don't care for!!"
Several of the characters use slight variants of their old Limit Breaks from the original game: aside from Omnislash, Cloud uses Blade Beam and what appears to be Braver, whilst Barret fires off a few Big Shots at Bahamut SIN.
Cloud actually gets two Bravers (one gets deflected off Kadaj, one knocks Bahamut to the ground) and two Blade Beams (the one in Forgotten City, then the three-beam version when he tries to hit Sephiroth and doesn't know where he's coming from). He uses a tornado-less version of Finishing Touch to launch Kadaj a thousand feet away just before the final fight. He also Climhazzards Bahamut's ass, and Tifa pounding Loz into the ground is basically her whole Limit Break combo just short of Final Heaven.
Even Aerith seems to get in on the fun. When Cloud and Kadaj start the previously mentioned fight in the church, the healing water she makes looks a lot like Great Gospel. What makes this scene even more awesome is how the water drives Kadaj away, and even seems to hurt him!
During the bucket-brigade Fastball Special, Aerith lends him a hand from within Tremor Flare. She used Fury Brand to let him Climhazzard Bahamut's ass immediately after his Braver!
Mentioned but worth pointing out in detail. Tifa Vs Loz. The first one on one fight of the movie. These are two lightning bruisers doing what they do best. All to a simple piano piece as opposed to a band or orchestra. Highlights include Loz whipping Tifa around by the leg and chucking her across the church, to her making a Three-Point Landing against the wall from said toss.
Oh come on. No mention of when Cloud is chasing after Kadaj, the Turks setting off fireworks to distract the other two. The fireworks happen to go off as Cloud rides off the guard rail; a very awesome moment.
That was mostly the shockwave causing him to waver course, but it's still awesome the way he uses it to his advantage.
He may be evil, but you can't deny that when Sephiroth sprouts his wing in Complete, it can only be described as sadistic, villainous awesomeness.
A sublime one if you're not looking out for it: When Kadaj takes control of the kids, they start looking for Jenova's head. They gather around the Meteorfall monument, prompting the Sephiroth Brothers to assume Jenova is buried beneath it. Then Shinra reveals he's got his under his cloak the whole time, and you realize even before they broke free, the kids knew Kadaj was bullshitting them and defied orders.