A huge upgrade over Remake in every way: gameplay, music, pacing, characters, side quests. The open-world checklist aspects can definitely be the sort of thing that annoys people, but it isn't that bad honestly. It's fun getting to run around, earning points to exchange for some really awesome materia while getting exp and doing side quests related to some of those checklist tasks. It really is just fun.
Right off the bat, the game has an amazing opening that it follows through on as the chapters progress, but more importantly it coalesces into an indescribably incredible and simultaneously confusing final chapter. Everything up till then is understandable and falls in line with the progression of OG (along with Vincent and Yuffie being non-optional now which means they get some great interactions with the rest of the cast), but that final chapter is when the plot really becomes its own. And the final fight, the genuine gauntlet that is the final boss is superb, and it amazes they did it: it makes me wonder what they're gonna do for the final fight of the third remake.
And the ending. It's amazing, so melancholic yet you almost can't focus on your sadness cuz there's something even more pressing going on, something way more pressing than the OG's plot.
Overall this game definitely cements the remakes as amazing titles, and I just hope the finale manages to stick the landing. I believe OG is still better as of now because it's a complete plot and it doesn't have the very spoiler-heavy plot point going on, but I think that if the final game can stick the landing then this game series will be on par with the original and serve as an amazing follow-up to it. But time will tell on that, for right now, Rebirth is an incredibly solid game and has me excited.

So take everything good I said about Remake, make it shorter and remove the pacing issues, and you get INTERmission.
Yuffie didn't have too much character in OG due to being optional, but I love how they expanded on her here. She's still definitely greedy, but she's also a good person, and her relationship and dynamic with Sonon was great. He quickly became a fav, and I loved all their moments together. They bounced off each other like rubber balls against a concrete wall, and I couldn't be happier. I think this was content completely original to Remake, so going with that thought it was fucking amazing. Like, they just absolutely know what they're doing. The story still had plenty of side content to do if I wanted, and I did do all of it except the board game, but the story doesn't dilly-dally and actually gets going a lot quicker than Remake, even though Remake starts with the iconic mission it quickly slowed down after that. INTERmission remains at a good pace the entire time, and even the short 5ish hour run time doesn't detract. It's fun, it's heartbreaking, Yuffie is fun as all hell to play as, and honestly it's my favourite part of Remake. It's honestly a perfect little DLC.

Off the bat, not as solid of a package as the OG 7 and that's partially due to the fact this is an incomplete story but also due to some very real and very obvious pacing issues. They clearly wanted to spend some more time in certain sections, as shown with all the side quests, but wow sometimes it comes to a screeching halt and it feels very slow.
But despite that, the game is absolutely amazing. Combat is incredibly fun, I enjoyed doing a hellish amount of damage with Cloud using staggers, and the way each of the 4 playable characters played was fun.
Story is still great and the ways in which this story subverts, or attempts to anyway, the original is great and lead to some very cute, awesome, and sad moments. Even the slow pacing doesn't take away from the Remake's original scenes, they're all a joy to witness for one reason or another, and even coming fresh off of 7 it didn't feel like I was treading old ground when so much of it was new. And I have to say, the ending just absolutely captured some of my favourite tropes, and it's an absolutely amazing homage to the final fight of the original. And the ending past that introducing new elements for the Remake canon is just hype inducing.
Music is great, too. So many awesome remixes, some great new tracks sprinkled here and there, and just a raw energy to some of them that make them just as memorable to the original.
Characters are portrayed awesomely by their VAs and getting to hear these characters coming to life makes me incredibly happy. Only one I'd say I have an issue with is Cloud's VA, he seems to be stilted in some pieces of dialogue that doesn't seem to be an intentional bit for his character. Regardless, characterization is awesome.
I think this Remake even if I give it a lower score than the OG game absolutely deserves praise for creating such a beautiful rendition and reimagining of the original Midgar section. It sets up so much, and I'm excited to see how it handles it in Rebirth.