This video would probably make a lot more sense to someone who has played FF16, so I'm a little out of the loop.
Of course with any GMV the footage limitations can be pretty detrimental to the editing process, but it feels like you did a good job with this. You set up the different characters with the different song verses and were fairly consistent maintaining which lyrics applied to which character.
I think this vid's strongest part is 3:46 to 4:21. The sync is tight for the most part, the chronology makes sense, and the visuals at 4:01 with the singer are beautiful.
Without having played the game, I can only make guesses for the rest of the vid, but the rest of the scene selection seems good but oddly paced more often than not. It seems like there's a lot of flashbacks, but the way they are put in this vid makes following the story confusing and disrupts the flow in my opinion.
There are some decisions that appear to sacrifice logical flow for beautiful imagery or noteworthy fan-favorite scenes (I'm speculating there), which is a thing that can be done, but in this vid seems to sacrifice some of the emotional depth due to those choices/placements. Or I could be reading too much into it.
For some more specific examples, 0:00 to 0:11. Begins with a close-up of the guy squinting at a cloaked figure that burns and then a close up of a hand using fire magic. The confusion starts early because it seems to me that black hair gets powers from the cloaked figure but has some misgivings about it - I make this assumption based on the hand montage. But watching the vid, I don't think that's what actually happens in the story.
You also have the cloaked figure turning away and going on fire at 0:02 but then immediately cut to the cloaked figure facing the camera, not on fire, but the town behind him is. By itself this isn't really something I'd normally complain about, but choices like this that upset chronology are scattered throughout the entire vid. You don't have to use scenes from the game in chronological order, but whatever sequence the scenes end up in should at least look they could have happened chronologically.
1:27 - 1:37 shows a very confusing timeline of events where I assume blonde guy figures out he has powers and they're a Big Deal(TM). But the ordering of the scenes combined with the white flashes don't seem to match anything currently going on with the music (the white flashes were especially jarring imo).
Another specific misgiving I have is with the ending. 3:46 - 4:21 is edited very strongly and is emotionally impactful. But everything leading up to it almost feels random with the way it was edited - like you were trying to fit in too many scenes because they meant something in-game.
It's okay to leave out important game scenes - your video can work fine (and maybe even better) without them. A more streamlined visual plot will guide viewers unfamiliar with the source to the emotional reaction you're looking for, and fans of your source will fill in the gaps with their own memories and experience.
In spite of the rest of this vid, 4:23 feels like a Big Nothing to complain about, but I'm going to mention it anyway because as I said I really loved 3:46 - 4:21.
You spent approximately 4 minutes telling this tale of two brothers who were separated, possibly hated eachother, reconnected, and then separated violently again. You spend almost an entire minute (3:46+) making me feel like Black hair was inconsolable with loneliness because he just lost this dude. You had a great transition at 4:14 visually showcasing how lonely this guy was, complete with the scene at 4:19 as the hope that maybe he wasn't actually alone after all.
And then the scene immediately following it is him hugging the dead body and crying.
Maybe it's just me, but 4:14+'s editing implies that time has passed and the body is no longer physically present. To show that everything that just happened (his loneliness and the feather) in between two scenes of him with the body implies that that sequence happened in his imagination.
I think you could've just faded to black after the feather scene and had a way more impactful ending, but at this point I'm just saying how I would edit your amv, so idk maybe ignore me, I just have feelings now and I hate you a little bit for that.
Your category suggestion of "sad" was accurate. But imagine how much SADDER you could've made me with some different editing decisions/scene selection!
note: I want to explicitly point out that me saying the video is sad is referring to the story of the video and not how it was edited. I am not trying to insult the editor.