I'll assume people are familiar with the original for most of it.
So lets get the easy stuff out of the way first, the game looks really good, both because the graphic are good but also because they put a lot of care into making the environment feel alive and have lots of clutter around, which really sell the slums. Almost worth playing just to walk around the environment. Unsurprisingly the soundtrack is great since its mostly the old songs again, although I'm not crazy about the added jazz spin to a lot of the song, some of the new song are also pretty decent, but they don't mix that well with the older one.
Onto gameplay. First we need to acknowledge that this game is not a turn base JRPG, its not an action RPG either, nor a spectacle fighter. This is a waifu simulator first and foremost. Most of the game time is dedicated to having Clound walking around with a slut lady clinging to his arm (or both arms in some case), you go on meanial side quest that bring nothing to the story, but hey w/e you got a girl with you. I'll go over that more later, but first now the important thing to realize is that the gamepley needed to be fairly uninteresting so that it didn't detract from the dates Cloud go on. Sadly for the dev, the combat department didn't get the memo and turned in a really good combat system, after the embarasement 15 dare to call a combat system, its shocking how good the combat. Now, sadly for the player, the encounter designer department did get the memo and did everything in their power to make the fight as uninteresting as possible, and they succeed beyond their wildest dream! For 75% of the game (ie, the waifu simulator parts) goons you fight in the world are so weak that they all die before you can start using the ATB charge you build up (which let you use magic/ability), they barely count as speed bump. But so what, JRPG always had weak crap to fight in between boss, the boss is where the real meat is right? Right?
Boss are embarrassingly bad. First of all, they're very scripted, at multiple specific health value, a cut scene will happens where the boss and Cloud fight, interrupting your fight, this is like playing a game with annoying older sibling that keep yanking the controller away from you because "your playing it wrong". Once this happens, the bosses stagger gauge is reset. Now the entire point of the combat system is to build up the stagger gauge of the enemy and unleash all your super attack when its full for extra damage, but there's very few boss where that actually matters because the second you stagger them, you'll exceed the health threshold for a cutscene and the boss will move on, often with your character just wildly flailing around, executing attacks for boss that have long move on. Now it is possible to very quickly stagger boss so that you have a bit more time to attack them while staggered, but that usually involves knowing what the bosses are weak too ahead of time, so that you can equip the right materia to everyone, but in most case only one of your character will have the correct materia. It's not like that matters, boss are incredibly easy since healing is plentiful and use to use. In my full playtrough on normal (hard is only unlock for new game+ for some reason) I only lost to boss twice, one was during the bike sequence at the end which doesn't use the regular combat system anyway and the second was the last boss, where you need to have materias equip to every characters in your party since they all get used, rather than just have 3 sets that you move around as needed. That's an important point because Ai controlled character are essentially useless and only serves to let you use an ability every once in awhile, but if they have no materia equip, they're kinda just there for decoration because of how passive they are and because they build up ATB incredibly slowly. Overall, I don't think I've ever played a game where the combat system was so constrained by poor encounter design, some of the optional fights in coliseum are actually really good because there's no cutscene to interrupt you and some of the monster are actually tough enough to warrant some strategy.
Otherwise, the game has a weapon leveling system, in theory its a nice system, in practice its just the worse. The system is very simple, every weapon has a list of passive that can be unlock (from stats boost to new materia to passive skills) using SP character gain from leveling. A UI with a simple list would have done the job perfectly well. But instead the system is presented as solar system with planets around them, every time you go in a weapon, there's a small cutscene to load the planets and you then have to navigate the planet (ie skills) sorta at random, finding the skill you want to unlock is a pita. But worse is that the UI doesn't show you all the passive the weapons have unless you're into the planet view, so comparing two weapon means going back and forth between them while seeing the animation every time. This is just pointless BS to make the system appear more complex than it is.
The materia system is nice because it was a nice system to begin with, although they severely reduce the impact of equipping materia on character stats, which is a bit of a shame since that just simplify a system that was never that deep. I was hoping for more passive materia and new action, but as is, there's less than in the original. Summon have been changed to only been summonable in tough fight, now they actually summon the creature to fight with you for awhile rather than just being magic with another name, but they're never worth using since Ai companion are super passive and you can't directly control them. Much better than FF15 system, but kinda of a waste.
Alright onto story, I'll try to mostly go over this as a standalone game not related to the first one first and then I'll go over the changes.
As said before, most of the game time is taken by going on dates with various girls. On the plus side, they're all really nice character, on the negative side, they all behave like super horny teenager the moment Cloud show up. Jesse is absolutely the worst for this, she probably has to carry a mop around to clean up the wet floor every time Cloud says anything to her. In the original, she was a bit flirty with Cloud, but that was understandable since he saved her (in a nice case of player involvement, this didn't happen in a cutscene, the players had to chose to save her) and it was just a few scenes since the Midgard sequence was just a few hours. But here she has far more lines than before, and they're almost all flirtatious, and she starts before Cloud saves her. One of the first thing she does is ask if Cloud is dating Tifa (maybe 10 mins into the game), at that point all Cloud did was being kinda of an ass to everyone in Avalanche. But this plagued every encounter with the girls, at some point Cloud, Tifa and Aerith fall into a sewer, if you check up on Tifa first, rather than ask if Aerith is okay, she immediately start asking Cloud if he's dating her WHILE SHE'S STILL UNCONSCIOUS (possibly dying for all they know) RIGHT NEXT TO THEM, GIRL GET YOUR HORMONE UNDER CONTROL! This made it incredibly hard to take any of the girls seriously. Barret sadly doesn't fare that much better, he comes of as the biggest idiot in the world, always yelling and angry at Cloud for no real reason (that's not inconsistent with the original, but the sheer number of cutscene really drive that home to the point of comical absurdity).
Overall the game has way too many cutscenes that are just pointless, the worse is the sequence when you have to rush back to sector 7 to stop Shinra from dropping a plate and killing everyone. Instead of hurrying as fast as possible, you instead have a cutscene every 10 minutes where the character just continuously ask if Shinra is really going to do this. Once would have made sense, but I think there's probably 4-5 of theses, they all end with them confirming that they have to hurry up, you know what would waste less time guys, STFU and keep moving! There's also many case of cut scene stupidity, I think on 3 separate occasion character will capture someone, just to have them escape by... just walking away. During the plate dropping sequence, 2 Turks try to activate the plate dropping sequence, but there's 3 of you (Cloud/Tifa/Barret) so it should be pretty easy to stop them, except Tifa just disappear form the cutscene, oops, maybe she doesn't care about the Slum?
But the game big problem are the villains. Shinra is impossible to take seriously right from the beginning, in this version of the game avalanche utterly fail at blowing up the first reactors, instead Shinra is the one who blow up the reactor for... no reason... Well that's not quite true, the reason is that the evil soulless corporation, that is square enix, was probably uncomfortable with the main character being terrorist who blow up reactor in densely populated city but at the same time they still want to have their big explosion, so they just have Shinra blow their own reactor, for no reason. I was rally hoping they were going to try to and do an effort at lampshading it, but no. This makes Shinra such a joke and really question why they bother dropping the plate to kill avalanche. Instead, just wait till they attack another reactor and blow it up while the group is still in it, that'll kill them and do far less damage than dropping a plate. In original, Shinra was ruthlessly calculative, better to drop a reactor plate now then let avalanche destroy all 6 remaining reactors. But here, all they have to do is not blow they're own reactor and they'll be fine. Even if you assume they're trying to drum up public support (for no reason, they have full power and the general population doesn't seem to particularly resent Shinra), why blow up the second reactor and drop the plate?
Onto Sephiroth. He's regularly consider one of the greatest villain ever and that's mainly for 2 reason:
1: He kill one of the main characters, this is pretty much guaranteed to be retconed.
2: The game does a really good job of building him up at the beginning. You never see him, you just see the aftermath of his passage. You storm Shinra HQ and ultimately get captured, but Sephiroth just walk in and fuck everything up and ultimately kill the president before you and you don't even see him once. He's just that badass and your group is completely worthless he can't even be bothered interacting with it. But in R, Sephiroth is obsessed with Cloud and stalks him everywhere. He constantly shows up in small pointless scene. This removes any mystery/mystique about him and makes him mundane and petty. At the end of the game we even fight against him, more or less to a draw.
Then there's the phantom of fate or w/e their name is. They're creature that tries to make the events happens along a certain paths (ie the original game) and correct any deviation. For the most, part they just help the group. Barret gets killed at some point and they immediately swoop in and revive him, not long after the group is almost squash by a falling highway, but they save everyone. Yet the group treat them like villains for no clear reason and decide to kill them, or maybe not, in classic Nomura fashion its really unclear what happens.
And so at the end of the game we have 3 villains, 2 of which we've already defeated and one we've fought to a draw. It's not clear why Sephiroth is so dangerous or needs to be stop, they says he's an enemy of the planet, but what does that means? All he does in the game is kill Shinra president, which we've been trying to do too. In the original you immediately transition to the flashback, in a good case of showing not telling you see why Cloud would have good reason to fear him and want him dead, but here's there's nothing, aside from a vague "enemy of the planet statement".
The game has plenty of great moment, the entire wall market sequence is super fun, escaping from Shinra tower on the highway is a badass way to end the game and Midgard is a fun concept as a city. But all these are just taken straight from the original, everything they changed makes things worse. Now, I don't think changes are inherently bad, I'll go over plenty of changes I wish they did later, but here taken individually, most changes just makes things worse. Beside, this is Nomura, of KH WTF story fame, of FF15 convoluted mess, of 3rd birthday, I wouldn't trust him with anything story related.
I already cover changing Shinra to blowing up their own reactor, just dumb.
Then you have multiple sequence of side quests, these aren't bad, but just pad the game and retread area you've already been to for the most part, they're mostly there for dating girls.
There's a new sequence where Jesse takes you to the top plate to see her parent and steal some explosive, this is actually a really nice sequence and I wish more of the changes where like this. The game expand on her backstory and reason for joining avalanche and you get to visit the top plate a bit to get a sense of what life is for most people living in Midgard (regular suburb). If all the changes where like this I would have really liked the game.
The train graveyard is much longer with some ghost kid interacting with Aerith, just more padding.
There's a new secret laboratory under the squashed sector 7, that's just more padding, nothings happens storywise. OH wedge survives the plate, w/e he's just a comic relief character
There's a long sequence in Shinra tower, where Hojo play around with your group for no clear reason, its jutst padding. Except you have to consatntly switch between various group configuration and that's really annoying since you have to move materias around every time manually.
At multiple point in the game they reference the fact that Cloud isn't a SOLDIER, I'm pretty sure even someone who's unfamiliar with the game would catch on playing the remake, this isn't a problem now, but cheapen the reveal later on. ALthough they seem to also have changed the event in the pass and Nibelheim, based on the conversation with Tifa, so maybe the reveal will be that Cloud was actually a SOLDIER?
Then there's the ending sequence which is just Nomura clusterfuck. The game is relatively grounded up to that point, but suddenly all that throws out the windows, you fight in the sky above Midgard while chunk of the city float around. Cloud is jumping around in the air and cutting train in half (gee that sure would have been useful when we were trying to hurry trough the train graveyard to save sector 7). You fight against a shadow monster the size of a skyscraper and then Sephiroth (how is the player suppose to take him seriously next time you fight him when you already beat him?). Ultimately none of that matters, you just go back to where you were before, Midgard is still fine, it was all a dream in the end? What a waste of time.
Now like I said, there's plenty I would have changes from the original, sadly none of that was done...
The whole Sephiroth clone things always felt pointless, at a couple of point in the original game you see clone/zombie of Sephiroth. This really devalue him as a villain and makes things too confusing for no reason. So of course they kept that and added some more for good measure, afterall confusing non sense = deep storytelling, right?
The end of the Shinra HQ part is also really lame, Rufus, a character you've never seen or even heard from before, show up and Cloud then challenge him to a duel, mano o mano. This feel like its supposed to be the final confrontation between long time rival, but this is literally the first time Cloud see him. You also never fight against him later on, he dies in a cutscene from the Ruby weapon, having never been relevant to the story. It would have been far better to introduce him earlier, maybe have him be the one who destroy the plate pillar so the player as a good reason to want to kill him. Maybe even try to imply that Rufus was the one giving the stupid order in Shinra (destroy the plate pillar and the reactors) in a bid to destabilize his father and take his place.
Sorta related, the Turks have always been a bit weird in the game, they try to portray them as amoral employee who just follow order without really caring one way or another. But that doesn't work when they're the one who destroy the plate pillar and are responsible for killing possibly upward of 100 000 peoples. There's a sequence in the original where you see them later on in the original and they're just on vacation so they don't even care about you and your group just leave without stopping them. In a vacuum its a really funny sequence. But this work when the villain are team rocket and they never really hurt people. As is, that's like a Jew finding Hitler top lieutenant on vacation in Argentina and being like, "w/e, guy was just doing his job". But the remake keeps that aspect, even tries to portray them as conflicted about it, except they still did it.
The ramake end with this weird sequence where you see Zack and Cloud outside Midgard, with Zack surviving to go to Midgard in some alternate reality. This is an implicit promise from the dev that they game will go in a different direction from now on. But why wait? Why not have Zack survive from the begining, have the same classic opening with Cloud jumping out of the train and fight some goons, only for another one to show up and take aim at Cloud, but just before he can shoot him, Zack also jump off the train in a similar maner to take that guy out with some sort of "Cloud you gotta be careful man, I keep telling you". And then have them go trough the event with Zack around, maybe stop the plate from falling, have him and Cloud compete for Corneo approval in dresses. Zack is a fun character so that would have been far more interesting than this half measure stuff we ended up getting.
Okay enough tipping, I'm actually pretty worried this won't post now.