I haven't done the "intermission" yet, but I think I can kick out a review of this. TLDR version: weak port but very fun to play overall.
Setting
The game is set in the city of Midgar, a circular city built on two levels. The more well-to-do live on top level while the poor live below it, under a steel sky. Around the outer edge are 8 huge mako reactors that power the city. While the poor do live in somewhat ramshackle buildings, nobody is starving in the streets.
Most of the people are fairly happy with the city, though the poor obviously aren't so happy about their place in the system. A few folks aren't liking the system, though. Not at all. They've noted that the landscape around Midgar is becoming devoid of life, particularly plants. One such group is Avalanche. You'll start out playing Cloud, a mercenary hired by Avalanche to bomb one of the mako reactors.
The world's technology level is modern, but mako energy is used to power that technology, and that energy is quite magical. The energy can sometimes clump together, forming jewels (called materia) that give weapons and armor the power to cast spells.
The city government is run by a large corporation called the Shinra Electric Power Company. Naturally, they are all evil down to their rotten little cores! Well, actually not. The president and most of the top execs are a nasty bunch, but most employees are just typical folks doing their typical jobs. (They also have a huge number of security personnel that are happy to give their lives for Shinra. It is a video game, after all.)
Gameplay
The gameplay is mostly a linear set of missions telling a story. You will follow the path, kill the enemies before you, follow the path some more, eventually kill a boss, and get story fed to you along the way. The story is quite good, and Square/Enix does cut scenes VERY well, so this worked out very well for me. If you don't want to see all that story stuff, though, you can pause them and chose the option to skip each cutscene and right click a bunch to hurry in-game dialog along.
Occasionally, the game will open up and let you freely roam around town. They give you some little, optional quests you can do, too. A few of the quests aren't bad, but most of them are pretty uninspiring excuses to get you to run around town or go back through an area to fight some monsters. Feel free to skip the ones that don't sound fun. (They even put one in early on to fight some giant rats. I really hope the devs were just trolling us with that one.)
This is very much a JRPG. You will not be customizing your character. You get a few choices in the story, but they don't appear to be all that consequential. The game is mostly about telling you a fixed story where you get to do all the many fight scenes yourself.
When characters level up, the character's HP and MP go up some automatically. However, you also get some weapon points to spend on several things the weapon can do. You can spend points to simply add to its attack power, or add a new materia slot to it, make your healing powers work better when your HP are low, and so on. What's more, instead of having to decide which weapons should get the points, all the weapons get the same points, so you are free to improve any/all your weapons. If you want to add to the physical attack on one weapon and the magical attack for another, then switch between the two as you move from area to area, go right on ahead.
Oh, and you can save anytime outside of battle. There are also checkpoint saves that are fairly frequent. (The healing power save points gave you in the original game shows up again as benches you can sit on to rest.)
Battles
This is an action JRPG for sure, so there's a lot of fighting. You'll have 1 to 3 characters in your party (the story dictates which characters). You'll control one character at a time, but you can switch any time.
The fights play out a little like a pause-on-space system. You flail away with your normal attacks, adding to a blue action bar as attacks hit and damage is taken. You can dodge and guard against attacks as well. When the bar gets half full, you can press space and do an action. Actions can be special moves, casting spells, or using items like healing potions. A few actions require the entire bar instead of just a half bar. You can also press space before the bar fills up to pause (well, nearly pause) the action - you just won't have any commands available.
If you don't want to keep flailing away, you can pick one of the 'classic' difficulty levels. When you use this, the character you control will attack without your input. You can simply keep an eye on everybody's health and action bars, then press space and select commands as needed. If something in battle happens and you want to take over, that's fine, just start providing input and the game will take it. Stop doing anything and the game will take over the controls again.
Something entirely new in the game is the stagger bar, located under the (yellow!) hit point bar. If you can fill the stagger bar up, the enemy will fall over, allowing you to wail on them for bonus damage. If you can unleash your stronger attacks while the enemy is prone like that, the battle will end quickly. So, you'll want to use some tactics to try and arrange for the enemies to stagger when your heaviest hitting shots are ready to go.
Here's the last 7 minutes of a boss fight I did. Leviathan is pretty huge, so dodging was pointless, but I tried a few times anyway. You'll also see a lot of interrupting here. At 1:25, Tifa tries to cast a lightning spell at Leviathan, but the monster dives below ground level before the spell fires off so it does no damage. Getting hit hard while casting a spell will cancel the spell, too.
View: https://youtu.be/glBzHxKY9_U
Materia
As mentioned above, materia provides magic spells to characters by putting them in slots found in armor and weapons. Spells aren't the only things that materia can do, though. Some materia will add hit points or mana points to the character. Some will provide special commands like a provoke or steal command. A few allow you to summon a powerful being to help fight for you. There's an impressive set, but you'll only be able to slot a few at a time.
Most interesting (IMHO) are the blue materia that alter how one of the other materias you have acts. There's one that makes the partner materia act on all targets instead of just one, so a healing spell will hit all of your characters instead of just one, or a fire spell will hit all enemies instead of just one. An elemental materia on a weapon can make the weapon do extra fire/ice/whatever damage. On armor, it will reduce damage from fire/ice/whatever - or even cancel it at high levels.
Most materia can gain levels, too. After enough use, your fire materia can cast more and more powerful fire spells, and your healing materia will cast better healing and regeneration spells. If you don't get them slotted, though, they don't gain levels and, as I said earlier, there are never enough slots. Just like in the original FF7, your decisions on what materia to slot will change how your game plays quite a lot!