Ok, I don't usually post much here, but I need to come in and plug Demon's Souls. If you own a PS3, you really should play Demon's Souls sooner or later.
I beat it one time (though I still haven't put any time into New Game+ due to my backlog), and I don't get why everyone keeps saying it is the hardest thing ever. It is challenging, and unforgiving, but not unreasonably hard, and never cheap. If you die, it is entirely your fault. Every. Single. Time. The controls are very responsive. I have no idea what the earlier poster was talking about on the controls. You do have a stamina gauge implemented, which depletes when you attack, dodge, and when you block attacks, but all that does is force you to pace and think about your actions rather than run in swinging away like an idiot. If you just charge in blindly, you'll get killed quite often. If you approach cautiously and with your shield ready, you'll do fine.
As far as the RPG part goes, it isn't anything like a JRPG. You control one character, third person camera, in real time. You have quite a selection of melee weapons that all handle differently, with different speed, power, reach, weight, attack motions, etc. as well as magic spells and a bow and arrow. All of these weapons can be upgraded along one or more different paths that each confer their own benefits or power enhancements that scale with different stats. There are 5 main worlds with several "levels" per world--although the levels are really just checkpoints/portals since the each world is one continuous environment--and a hub world. The 5 main worlds can be tackled in any order, even doing part of one then part of another. You will be able to find merchants and magic teachers both in the hub world and in places in the other worlds (though the hub world is really the only "safe" town-like area). There are starting classes, though that really only determines your initial stat spread and starting equipment; any class can use any weapon, armor, or magic with equal proficiency as long as their stats meet the requirements. So really as the game goes on the "class" becomes meaningless.
Souls collected from fallen enemies are the main and only currency of the game, used both to buy weapons, armor, and supplies from merchants and to pay for level ups which are granted in the hub world. If you die, you go back to the hub world and lose all souls collected to that point, but you leave behind a bloodstain. If you can make it back to that bloodstain without dying again, you will recover those lost souls. If you die again on the way, you leave a new bloodstain with your current soul count which overwrites the previous bloodstain. If you are online, you will be able to see the bloodstains of other players, and watch a phantom replay their last moments before death. It can be frustrating to lose a lot of souls due to carelessness, but you can and probably should be using those souls on a regular basis to buy level ups, repair your equipment, stock up on arrows and other items, etc. so that you usually won't have too many on hand at any given time. And there are a few tricks for soul farming if you need them.
The most important thing is to be careful, get to know both your enemies and your weapons, never just rush in, and learn from your mistakes. The combat is quite good and gives you plenty of options for handling each encounter.
So, this post is getting pretty long already, but the tl;dr version is that Demon's Souls truly is an awesome game that any PS3 owner should at least try. Watch some Let's Plays if you want to know more about the gameplay.