So I just beat Dark Souls 1 for the first time last week and all I can say is: wow, what a wild ride. Despite it's noterioty for being difficult and the learning curve, I was surprised at just how fast I was able to learn and properly play the game. There were a few areas that I struggled with that are documented in this thread, particularly Ornstein and Smough, (aka Two Super Londo Friends Play: Kill the Chosen Undead) as well as Black Dragon Kalameet, but the rest of the bosses and areas within the game were fairly straightforward and not as hard as I would have thought.
The DLC area's bosses are much tougher, and I would say that they were the only bosses in the game that made me feel like I was fighting something that lived up to the infamous "Souls difficulty." Artorias felt as if I was fighting a human player at times, and Kalameet was a piece of work since I was a melee only character. Manus wasn't too difficult, but the challenge was present.
It also took me a while to get Gwyn's pattern down before I killed him, which ended up being not that hard in retrospect, but I really loved the presentation of his battle.
After beating Gwyn I wanted to go back to the bonfire to spend my souls before NG+, but then I ended up getting the Dark Lord ending, and I wasn't aware that there was more than one ending :/
Dipped my feet into NG+ a little after that and it felt so good killing the asylum demon in 3 hits. I think I'm gonna spend a little more time in NG+ before properly settling into Dark Souls 2 though, because I tried that game out and it feels completely different lol.