You'll either love it or hate it. I for one, enjoy it and here's why.
I am glad to say my expectations were met and i feel this was a worthy sequel.
I'm just going to address a few things and get it out there quickly so you can get an idea before you decide to buy it, because you're simply going to love or hate it. (no spoilers here either)
Difficulty
I've read time and time again that this game is hard. Playing it through twice, i can say that initially it might seem that way. As you enter the game, the initial stages may indeed have you dying and struggling to get through it. If you remain calm and don't write off the game, taking the time to learn from your mistakes, this feeling quickly fades. The game isn't too difficult and it's certainly not as bad as some other reviewers have made it out to be. You simple need to remain patient and learn without throwing a tantrum and you'll notice the steep hill turns into a nice challenge within a couple of hours. At this point, you'll simply find yourself testing your skills on each boss, learning and actually feeling some satisfaction when you beat a tough boss. Once you've finished the games boss, you may play through again with game+. This sees that steep hill return and invites you to play through with a greater challenge. In my opinion you've already gotten more then your moneys worth by the time you get here in any where between 50 and 100 hours depending on the player. I will quickly note that players with a short temper should not bother. You will die from the start and you wont enjoy it. But anyone with a cool head and anyone that can approach the game logically, will enjoy the challenge of advancing.
Graphics
I've heard a lot that the graphics suck too. They're not amazing. But the environments still looked great, you still felt part of a dark world. People are quick to write it off and i've seen many people mark it down in this department before playing past 10 hours of the game. There are some truly beautiful places here to be seen, despite it not being the best looking game out there. But hey, if you're willing to put a good game aside because it's looks are not up to your standards, then go and play something else, it's your loss.
Gameplay
It's fun. Takes a bit of getting used to, but there's a lot of skill involved. It's not one of those games where you're going to be too weak or completely godlike at any point. If you're having trouble, go elsewhere, level and return. As for being godly, it simply doesn't happen on your first play through. You'll always be challenged.
Story/NPCs
Like its predecessor, Dark Souls is not a story driven RPG. You don't find yourself advancing for the sake of the story, it's more for the sake of advancing. The NPCs you encounter are all very distant. None of them involve dialogue options and it's often difficult to tell how you're actually able to interact with them. They can all die and you can finish the game without any of them. That said, they are all 'characters' in their own right. I for one will always remember some of the characters encountered in this game. They say a lot, without saying anything at all. All in all, i feel the story and the NPCs help to make the dark and eerie world you'll be put into. You're very much alone most of the time and it seems the people around are just as distant. But it's also interesting to see how some decisions you might make, even unintentionally, can effect the people around you and your game play(if only a little). Lastly, if you're in it for the story, go and pick up Skyrim.
Online Play
My first play through i did offline. I didn't want help beating anyone and i didnt want to be attacked whilst i played through. My second play through i did online and quite enjoyed the thrill of being attacked at any moment. Or invading. The way it works is very unusual and i wouldn't say you'd play purely to PvP like you might in other games. It's very much a nice touch to the experience, but, not really a PvP game.
It's sometimes nice to help people take down a hard boss too.
The Bad
Why didn't i give it a ten? Well there were little things where i got cheaply killed or maybe experienced a little bug. These i'm not marking it down on, you get them in any game. I noticed some slow down in a particular area, that seems to be common and may have been fixed by the time of my review.
The reason im marking it down is because of how the armor system works. I won't be going into too much detail on it, but i can just say that you'll be using medium or heavy armor. My second character was a very stealth/assassin type character purely so i could make it that much harder. When every hit can kill you and you're relying on dodging entirely with two daggers as weapons, this game takes it to a new level of difficult. In my eyes, i used light armors inefficiency to improve my game experience. But i just think it didn't work as they'd intended. Minor things really.
Overall
It's a good game. I spent a great deal of time playing it and was never bored. I was on my toes the whole time, carefully advancing, something ive not experienced since demons souls. I won't say it's BETTER then its predecessor, because i don't think it's true. There is a certain experience only they can offer as far as the gaming market is concerned. But it's definitely not a let down. A bit different, but ultimately worth playing.
I do miss the maiden in black here:P