These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
"One Winged Angel" is back (in a metal version), and it's cooler than ever. The other Black Mages remixes are pretty awesome, too.
Divinity I, complete with Ominous Latin Chanting, complements the impending destruction that Bahamut rains down on Edge, whilst Divinity II is more epic, coming to a climax as Cloud faces Bahamut with the help of his old allies. Some of Uematsu's best work with a full orchestra.
The ending songs: Calling (original) and Safe and Sound (Complete).
"Opening" (An orchestral rearranging of the song that plays during the original game's Title Drop)
"Battle in The Forgotten City" can count too. It's pace complements the Cloud's arrival to The Forgotten City being attacked by Yazoo and Loz; then Kadaj walking towards him, and finally the actual fight.
"The Promised Land" (the song that plays during Marlene's narration and after the battle with Sephiroth.
"Those Who Fight" (An industrial metal remix of the iconic battle theme from the original game)
Let's not forget the piano version that plays in Tifa's fight.
Flanderization: Cloud's angsting went from pretty minor in the original game to taking over his characterization here. At the end of the game, he seeemed to be mostly over his issues. On the other hand, Word Of God says that depression is a standard side effect of geostigma. On the other, other hand, Word Of God also says that they deliberately regressed Cloud's emotional state so he'd feel more "familiar" to viewers, making the geostigma side effect just a justification for that.
Magnificent Bastard: Rufus Shinra - He spends most of the film pretending to be a cripple, and has Jenova's head with him the entire time. The reveal of this comes with Rufus going full on Magnificent Bastard as he openly mocks Kadaj for never figuring it out, simply remarking "A good son would've known." Then, he jumps off a building, basically depending on the fact that the Turks will stop him hitting the ground (which of course they do).
Memetic Molester: Certain fans have gone on to characterise the Silver Haired Men, but especially Kadaj, as paedophiles. The sad thing is that that isn't far-off how their mass child-kidnapping
"There's not a thing I don't cherish!" So really Cloud, you value everything in existence? That's either Narm or a hell of a Papa Wolf.
BANANA
Narm: In the English dub when Reno and Rude are taunting Loz and Yazoo during their fight by insulting Jenova. It was actually a pretty intense fight but due to the previously mentioned Lip Lock, the best comeback the dub team could come up with? "You meanie!"
Never Live It Down: You can thank this film for hogtying Cloud to the term "emo".
"For every battle, there was more sadness. Someone I loved went back to the Lifestream too."
"Please don't take Denzel away..."
Denzel's OVA is one long Trauma Conga Line with occasional Hope Spots. His parents are killed when Sector 7 is destroyed. His caretakers after that die from Geostigma. The others kids in the scavenger gang he joined all move on one by one, and a thoughtless comment ruins his relationship with his last remaining friend. By the end, he's teetering on the edge of the Despair Event Horizon and considering suicide until he meets Cloud.
Toy Ship: Some people appear to like Denzel/Moogle Girl. Especially once Advent Children Complete came out, and they got more scenes together. There's also Denzel/Marlene for others.
Wangst: Cloud, though he actually gets over it about halfway through the film and says so.