Staying its system deep in jRPG schemes, Persona 2 brings with its overlay a breath of fresh air into RPG dungeon.
Before I will focus on plot I want to explain this is not strict sequel of Revelations: Persona, yeah you will find characters form first game and it's the same world, however between Revelations and Eternal Punishment there is a one more game also with 2 in title named Innocent Sin which EP is direct continuation that show second half of the story. Not knowing IS won't affect understanding plot of EP but you better know that thanks to Sony idiotic policy we were robed form another 70 hours of gameplay and half of the story.
Anyway despite all that situation what you need to know for the beginning is that you are Maya Amano a quite young and attractive (of course if you don't consider big boobs and whore-like-outfit as a absolutely necessary condition for female character to be attractive) who is send by her old and unmarried female editor (such are the worst I know from experience) to investigate Joker curse case. Joker is a fancy guy who look like a creepy queer clown (such are the best,and don't ask me do I know it form experience) who kill everyone you want (including your mum and dad and even that old, now heated, best friend) if you just call on your own number. That's just a prelude to bigger case that will involve japan government authorities, one psychopath, Carl Jung's theories and lot of other interesting things I don't want to tell you about.
Game at it's basic structure is quite classic RPG with random fights and dungeons full of devils and fiends that waiting to have their butt kicked (or they will kick yours if you're not good enough). What differ Persona series from such games like Final Fantasy is that every character have a Persona (yeah I know, brilliant conclusion). This is an alter ego of characters with it's own abilities and weaknesses that affect its owner. Also Personae can level up also learning new moves and spells. There are several Personae to summon, you do that by using tarot cards in special "shop" named Velvet Room (one of the most stylish locations I saw in video games and looks like taken form some Lynch's movie). You can not only summon Persona but also add some special abilities or points to statistics for every new Persona you make and later (after it reaches highest level) return it and receive item.
Returning to combat you have typical commands like Item or physical attack but also you can use Persona and talk to demons. Talking is the way you obtain tarot cards that later are used to summon Personae (or change to different one). Every character have its own style in conversation and every demon have it's own type of personality so point is to mix characters in such way so their style will fit demon's personality. If you amuse demon he or her might want to have "contract" with you so during next meeting you can obtain blank tarot cards (needed to summon some Personae) item or money but you can have only 3 contracts at the time.
Battle can be be strange for the first look because there is no turns you just choose command and fight start. You can stop it every time and choose new commands if you see that your characters receive quite a massive damage. Also you can choose in battle options to stop fight after last command is finished so you won't get killed because you forgot to stop fight. Last things about battle I want to write are fusion spells. It's combinations of persona attacks you discover during fight and that requires 2 or 3 characters. Such attacks are often very powerful and are essential to get progress in later fights when enemies are getting really strong.
Other very important element but not connected to battle is rumor system. Story of games allows rumors to come true (that's why Joker curse become real) so your task is to collect rumors form meet people and spread them. This way you can get access to special shops, items, quests or even dungeons. What is worth mentioning game despite long main scenario there are quite many sub-quests that can take another 20-30 hours from your life. If that's not enough you have second path of scenario that give you different character in the party and one different dungeon in main plot.
But forget about game system and focus on what I find in Persona 2 most interesting and worth praising is the style of this game. What I mean by that? Design, story, characters and impression that they create. It's not a typical boy-with-amnesia -and-girl-from-lost-kingdom-saves-the-world-from-evil-bad-guy. Yes, it has lot of typical for jRPGs elements and in it's core it's like other game of this genre but fact that plot take place in present time and your party contain of Adult people (yes, no 9-years-old-kids-with-big swords!). Story is very depressing and deep not only in fact it base on Jung's theories, Lovecraft's monsters and many ancient mythologies but relations between characters and way they are presented is more subtle that usually.
The only big disadvantage I can think of is dissonance between atmosphere the story generates and audio/visual side. Don't get me wrong music is nice (and in dungeons even awesome) and graphic is quite low tech but still it won't hurt your eyes (plus there are sweet artworks in conversation screens), however music and graphic style seems be too "happy" for such depressing game. Making it look and sound more "dark" would benefit the game in its overlay atmosphere. Moreover it's a pity that we can't see artworks showing our Personae in their full beauty. Kaneko made great work but in game due to specific game style we can't see all greatness of it. Anyway that's all of bad things I can say about this game maybe other minus is that prices of items are high but that's all I can think of.
To summarise what I want to say is that Persona 2 is maybe low-tech and quite oldschool-ish now but if you search for jRPG a bit (or maybe even more than a bit) different than what you can find usually in this genre it's a good choice. The game is long, difficult (but not so hardcore as some Shin Megami Tensei games), with great plot and one of most cool characters I ever seen in jRPGs. So if you expect something more from jRPG than good look and geyser of special effects you should give it a try.