I beat DS2 a month ago and it's great, although definitely a downgrade from it's predecessor. What I liked about the first game the most was the map/level design, exploration, and how the areas are all beautifully connected together. The overall map and world was overlapped, areas were on top of each other and that kind of stuff. DS2's map is flat, just flat. Pretty much no shortcuts or connections between areas except for 1 connection which you use to get to the area the first time. There are many more areas compared to the first DS and that's not a bad thing, but they're also not as memorable at all. Which brings us to another point, the bosses are a HUGE downgrade. You remember when you cried when you found out Sif's story, when you figured out Ornstein and Smough's relationship, and the different cutscenes you get when you kill one before the other, or when you heard The White Witch's dialogue after Quelaag? Yeah, no more of that in DS2. You just go in, kill the boss, and most of them have a very vague backstory if any, and that's it. DS1 it was comparable to SotC in the fact that you feel like you're killing the bosses because you're forced to while they really did nothing bad and were in peace, that didn't exist in DS2.
That's not to say it's a bad game though. It's pretty damn awesome and didn't do the Souls series any damage, but DS1 was simply better. Even in terms of gameplay, DS2 has some sloppy flaws when it comes to hitboxes and animations, unlike DS1's smoothness.
I'm also almost done with NG+, which was challenging so far. DEX build sucks major, major major ass btw.