Casual RPG fans need not apply.
And when I say, old-school, I mean it. I have a feeling this was a bit of a throwback even back when it was originally released on Sega Saturn. This is not a game that walks you through every possible option and method of gameplay. You are left to figure it out yourself and while this leads to a few frustrating snags here and there, it is well designed enough that ultimately learning the ins and outs of the game is satisfying in its own right. The graphics, aside from a few cut scenes, are strictly static images and dungeons are endless chains of seemingly identical looking 3D passages--though there is an automap feature, mercifully, and this is not so old-school as to have you drawing maps on sheets of graph paper.
The setting for Soul Hackers is in near future Japan. The main character, who you get to name, is a computer hacker and it is a heady time for hackers indeed. You live in a model city called Amami City which includes a virtual world called Paradigm X that presumably Amami City residents will spend most of their time in once it's fully online. Your first act in the game is hacking into the city's servers and putting yourself on the list of beta testers for Paradigm X. As you might expect, you learn pretty soon that things are not as simple as they seem from the surface.
Almost immediately after you try the beta, the leader of your Hacker group finds a strange computer shaped like a gun and it turns out you are the only one who can use it. In investigating this further, a demon pops out of the machine and takes possession of your best and maybe girl friend, which seems to be greeting w/ much less surprise than you would actually expect. It turns out this gun-shaped PC has the ability to capture the souls of the demons you meet in combat and you can recruit them to join your party.
Recruiting demons becomes an essential part of gameplay and figuring out the whole system is where the most satisfying challenge of Soul Hackers comes from. You recruit demons by talking to them in combat and they will or won't join your party for a wide variety of reasons you have to figure out. Once you have the demons in your party, they do not level up so you are forced to continually recruit new demons in order to keep your party strong. In addition to this, you can fuse multiple demons into (usually) stronger ones and also use your demons to create powerful weapons and items. There is in game instruction for all of this but you will end up learning most of this stuff through trial-and-error.
The majority of the game is spent in 3D dungeons a la Phantasy Star. You plod along one square at a time and everything looks really samey and, frankly, pretty bland. Somehow though, this really works for Soul Hackers and combined w/ sincerely excellent soundtrack music, creates an atmosphere of tension and foreboding. Enemy encounters are random and combat itself is turn-based w/ only very minimal animations--again, this was old-school even back in the nineties. You can normally avoid having to fight enemies by talking to them but then you cease to collect Magnetite which functions both as sort of a currency and as fuel for the demons. This need as well the need to continually upgrade your party through recruiting demons helps break up the seemingly endless dungeons and also keeps your characters properly leveled throughout the game. On paper, I cannot figure out a way to make this sound anything but tedious but the pacing only very rarely feels too slow or cheaply drawn out--and that is a rare quality for an older RPG with around fifty hours of gameplay to have.
Overall, there are few tough bosses that will give you headaches but the difficulty curve for Soul Hackers is not too great--especially since early on you get a device that lets you save at any moment you want. You also have the option to raise or lower the difficulty level at any point you want. I am not sure if there are going to be many people picking up this M-rated game who will want to dumb it down but, hey, the option is there if that's what you want. I found I did need to grind a level or two on occasion to get through w/o cheating but the inconvenience there was quite minimal. One level can really gain you a lot of extra firepower since it not only raises your own power but lets you recruit more powerful demons as well.
As I mentioned, this is my first experience w/ the series so I am not sure how Soul Hackers stacks up to Persona or other SMT games. I can tell you though that, taken on its own, this game is a great experience. You need to have enough persistence to learn its ins and outs on your own but once you do, this is a very satisfying old-school RPG which you are sure to like if you are the kind of person who likes old-school RPGs.