Shipwreck said he can beat Ninja Gaiden pretty easily, but I recall him saying he didn't get past the Chapter 3 boss in Ninja Gaiden 2. That being said Shipwreck, what's harder: Ninja Gaiden 2 (Not Sigma) or Demon's Souls?
Oh, and Wombat just made my list for that Uncharted revelation.
Like I said, it's a different skill set. I actually progressed pretty far into Ninja Gaiden 2 on the 360 before hitting a hard section and then getting distracted by something else (plus I thought the game was a big let down from the original game). I did get stuck on that Chapter 3 boss for a little while until I figured out the pattern and what weapons/Ninpo to use. I don't have any doubts that I could get through the remainder of that game if I went back to it though.
I think it's the structure of Demon's Souls and having to repeat large portions of the game if you don't block or dodge a single blow that makes it much more difficult than the Ninja Gaiden games.