Jonric: How much playing time can the average player expect, and what degree of replayability? And why should someone who didn't play the first one want to try the sequel?

Ferret Baudoin: The number of hours is a tricky thing to quantify - we're shooting for 30 to 40 hours of dungeon-romping, plot-twisting and monster-slaying fun. But mileage can vary widely on this.

As far as replayability, there are a lot of choices - some major ones - that lead to very different play experiences. Beyond that, I still play through Hordes of the Underdark for - err - research because playing through D&D games as a Wizard is a very different experience than a Monk.