OK I just killed my first Demon. That was awesome, and I bet this game will keep me occupied for a long time. It is just so awesome and addictive. I love the difficulty... it really adds to the game. It was frustrating at first, because I was approaching it like a typical RPG. I am glad I stuck with it, because it is really sweet. You just have to pick your battles, and not be afraid to use hit and run tactics. Really, there is so much about the difficulty that feels old school to me. This was what so many games were like back in the day.
The action elements are good enough to stand on their own, really.
Now that I've killed my first demon, I am going to stay alive and grind my stats up a little.
Also, if you somehow see a message near the top of the nexus about finding true love if you jump off... that's from me heh.
I also love the whole atmosphere they've put together. This is such a unique little gem, Demon's Souls is.
edit:
I agree with what Que said early. If Yahtzee is a reviewer worth his salt, he should have recognized the good stuff in the game, even if he didn't like it as a whole.