It's funny, before they announced the remake (like, right before) I started playing the original on my Vita. It was a little clunky but I could appreciate what they were trying to do. Maybe it's just playing on a full console or using a PS5 controller, but Reunion is definitely a lot more fluid. Main complaint is that it gets spammy toward the later chapters, while also being insultingly easy (yet hard unless you abuse fusion for higher rank missions).
I liked how they built up Zack's character, and how so many different people end up liking him throughout the game from the odd favors he does. His relationship with Aerith was decent, though I feel the writing didn't do it favors. It's strange because the world building and characters Zack met in the missions were great, but the missions themselves were a slog. I tried nearly half of them and I burnt out hardcore, it was just the same few maps and fights. Thankfully they were quick, but even so there are more games I want to play (especially FF7R Intermission prior to Rebirth) so I gave up on doing them. With all of the similarities to FF7R, seems like it might be a game better revisited after Rebirth or part 3, depending on how things end up.