Nocturne is one of my favorite games of all time. Granted, it was my comfort during during a pretty traumatic time in my life in which I was bed ridden for several months so YMMV.

Some things to know about Nocturne:

This is where the majority of persona designs come from. It does not have the extreme stylized menus but this is to my knowledge the first appearance of those 3D models later reused in P3 and P4 and DDS and DS.

The combat system is very similar to P3 and P4. They call it the press turn system or something like that. There's a lot of cool extreme "beat this guy with 1 press turn icon" where you have to abuse the system to win style challenges.

You only get Dante or Raidou in your party if you go with the true demon ending. And let me tell you those last couple boss rights in true demon are ridiculously hard (harder than end boss in P3).

One of the true demon skills you get is called pierce which is amazing until you encounter a boss that wipes you for having it. I'm pretty sure this is the SMT game where if you go into battle with certain skills equipped it automatically wipes you. But that might be DDS.

The strategy guide for this has a lot of cool interviews and series info. The fiends are a big deal in this game and were rare encounters in previous games. The fiends being the skeleton faced guys (Trumpeteer, Matador, White/Black/Red Rider, Mother of Harlots, I forget who else)

There's a lot of story in this game kind of like there's a lot of story in Dark Souls. Its mostly up to you to figure it out. There are cut scenes and some conversations and some characters but mostly its your demi-fiend alone in a party with his demons.

Bunch of endings all determined by the choices you make in terms of remaking the world. Did I mention this game opens with an apocalypse and the whole point is to petition god to remake the world? I mean they don't call it god, but I mean, that's what they're saying.

A really cool feature is a lot of the NPC's that die can be fused/summoned later. The manikan characters are what I particularly remember. Dante/Raidou are just party members though, no summoning them.

The main character gains skills by leveling up equipped magatama. Can't relearn a skill you've already gotten rid of. Don't know if they changed that in the upcoming re-release but it doesn't sound like they changed a lot so expect that. Plan accordingly.

Plan on grinding out the summon book. Use demons of the Element (Mitama) variety to fuse with a demon to get the next level up or down demon in that demon's family (similiar to Persona 5's treasure personas you find)