It's very cool. I put a good 4 or so hours into it last night and had a total blast. It's totally unlike anything I've ever played, at least to a point. It reminds me heavily of the old Codemasters game Blade of Darkness (aka Severance in Europe and elsewhere). That game was very dark, gritty fantasy with relatively punishing difficulty and felt like a mix of an RPG and action game. That one veered more toward pure action, but it was quite cool. They're also both a bit wonky in spots which can add to the frustration. The one thing that Severance had that Demon's Souls really doesn't was absolutely fucking epic gratuitous violence. Some of the best blood effects to ever grace a PC monitor were in that game, I tell you. Little stands up to it even today. Demon's Souls is plenty violent, but -- sadly -- not graphic. The game also reminds me a bit of Draconus: Cult of the Wyrm for the Dreamcast, which was a fucking fantastic game.
Anyway, for those who no longer trust reviews, I'll give an overview you can trust.
The game is unique for the following reasons:
A - It's hard. But not like a little hard, like fuck you hard.
B - The game combines the single-player experience with the multiplayer experience in really neat ways.
C - The game feels both linear and moderately open at the same time.
D - It has a phenomenally surreal feel to it.
Firstly, the difficulty. While it is hard, the real extent of that will depend on who you are and what pisses you off. For me, I don't really find it all that bad. I did die a number of times in the opening level, and a couple of them were cheap deaths related to wonky bits of the game (I once walked off a ledge by accident because my target fell into a pit and shifted my viewpoint before I could untarget him or stop moving), but on the whole you feel as though you learn from your death and have a better idea of what not to do next time. You may die some stupid deaths, and these can be a little vexing, but if you learn to slow down and play every life as though it were your last, you'll be fine. It's not that much worse than anything else, you just can't save and load or restart from a checkpoint.
That said, you do kind of get checkpoints, or at least the first area worked this way. It isn't that you'll be able to start from where you left off, it's that the things you do in the level are persistent. Enemies respawn every time you die or leave, but the actual level remains as you left it. Drop a drawbridge or open a portcullis and you won't have to do it again, which may make your life a good deal easier as far as getting back to where you want to be.
But do expect to go through the same areas and enemies a whole lot if you die. Your bloodstain will remain where you died, along with all the souls (basically the game's currency) you had at the time of your demise, but if you die trying to get back to collect them, only your latest bloodstain remains, which will obviously have substantially less souls with it. I lost a couple thousand to a stupid death at the hands of a weak enemy last night, and it was pretty crushing to know that what should have been a pretty easy corpse run that would have netted me about 2500 souls ended with a much easier corpse run to my new bloodstain that netted me a total of about 50 souls for the couple enemies I killed. I ended the night at around 6000, and I can say that having them so easily taken away makes a successful adventure all the more satisfying.
And that's what the game tries to do: reward you for not being a pussy. It does this very well so far. If you persevere, you will make progress and feel satisfied. If you give up fast, you will feel like you wasted sixty bucks.
That brings us to the multiplayer stuff nicely. The best part? Watching people die. The gimmick with the MP is that it's only sort of MP. You actually almost feel like you're in an MMO because you're constantly seeing the ghosts of other people running around for a few seconds doing something before they fade away, but you can't interact with them in any way and they aren't taking part in your world, they're in their own. But when they die, they leave bloodstains that may randomly show up in your world. "Use" them, and you get to view the last few seconds of their misspent life. The thing is, some of these are really fucking funny. Some of them are just like, "A guy was fighting and obviously got stabbed to death right here," but others are like, "A guy was walking up this staircase and... uh, sort of walked off of it," or, "This guy was doing pretty well until he dodged his way into this campfire and burned to death." The noob-deaths are just immensely satisfying to watch, even though you have to use your imagination for some of them, and they make you feel like a total badass when you're doing well because you're constantly seeing all these places that other people are dying but you aren't. It has quite an interesting effect on your psyche.
The other really neat part is that players can leave messages. You just drop one on the ground using the selection of pre-set things they offer you, usually to warn people of an ambush or trap, or maybe point out some treasure or something. Then your messages will randomly show up in other people's games, and if they think it was a good message, they can "recommend" it and thereby refill your health. Some messages get totally looked over where others get a ton of recommendations, and some people put great messages where some are kind of "what the hell was he trying to say?" Too, you could totally lie just to fuck with people, and some of those messages can be pretty amusing.
I haven't experienced the coop or PvP play yet, though one of the cool things is you can't opt out of PvP. The game continues to be hardcore, here. Basically if you die, you can come back to life in your own game either by helping someone defeat a boss in their world, or by invading their world and assassinating them. So while you can choose to participate in the coop stuff by either asking people to come help you or choosing to go help someone so as to bring yourself back to life, you can't opt out of PvP. Somebody may invade your world at any time if they choose to do so. And, of course, you can try to kill somebody to get yourself back in your own game, too. I only just got the items that allow you to deal with either of these things, so I can't report on it, but the concept is pretty cool.
I sort of already mentioned the third item, that the game feels linear and a bit open simultaneously. This isn't eactly true, but has more to do with the feeling of it. As I mentioned, levels change and stay changed as you do certain things in them, even though enemies always respawn. Since you're also seeing other players doing stuff and reading their messages, it really feels kinda' MMO-like, despite not being like one at all. But it doesn't feel lonely. And since enemies respawn, you feel like you can go back through areas just to farm stuff from them... and there are areas that may be harder or easier, and new paths can apparently open up depending on how many people have died or kicked ass, etc. I don't know about that part really yet, but supposedly things can shift around depending on what people do. Doesn't drastically alter things, just gives you a change. And when you go through a level after death, your next experience may be a little different too, since enemies can occasionally be unpredictable or a change in the level may make stuff slightly different.
Anyway, I've noticed some diverging paths in the first area, and even after defeating the boss, there's still stuff to do there. But I don't have to. I could also check out any of the other levels if I wanted. So while the levels seem like they'll be somewhat linear, you also have some freedom, and there are definitely areas you don't have to go to that may yield more stuff, and sometimes there are multiple paths to an end destination.
This is getting long, so lastly, the atmosphere is neat. The gritty, dark fantasy feel is great, but the fact that you've got all these other people running around leaving messages and popping in and out of view, dying to warn you of things, etc., works with the art and design they've gone for to really make things feel quite surreal. It's pretty cool and makes the general experience feel very different from other games. You never feel alone, but at the same time there's a heavy disconnect from other players. Even when you're doing coop you can only do a limited set of gestures to communicate. It's really pretty cool how that feels.
Anyway, I highly recommend the game. But do know whether or not you've got the balls to stick with it before you buy it, or at least force yourself to stick with it even if you get frustrated. In the end, it seems like your frustration gets amply rewarded by the game's systems, and there's a lot more depth to this than other games I've played that felt similar.