Worthy sequel to a better predecessor.
Yet, it doesn't approach the grandeur of its predecessor. As with other games we've seen (Mass Effect, for instance), the developer clearly holds back in order to reserve material for the inevitable sequel. So much so in fact that the story feels unfinished and rushed in the third chapter.
There are other issues: the difficulty is uneven; the prologue includes extremely frustrating cinematic sequences where you have to press different buttons under time pressure (failure=death). Similar sequences exist at the end of boss battles. Frustration is guaranteed. Once you've finished the first chapter though, the game becomes too easy.
Throughout the second chapter I was waiting for the opportunity to construct a set of armour. The game keeps you waiting essentially until the end of the game, where suddenly 3 or 4 similarly impressive armours are available.
Levelling up can happen two levels at a time when you conclude some important quests, while hunting for monsters gives you next to nothing.
So there are serious gameplay issues. That said, the Witcher 2 has a lot going for it. CD Projekt RED has skyrocketed into a position where they lead rather than follow. These guys know how to make a first class role playing game. They've succeeded in turning a fantasy book series into a great game, but it's not all perfect.