The Witcher 2 - Previews @ Joystiq, Eurogamer

Joystiq has a preview of The Witcher 2 called "Cause and effect", as they describe a quest sequence about disappearing men:

Like the first game, The Witcher 2 leaves much of its storytelling to be unraveled by the most investigative of players. Once I picked up the quest, an entry was added to the game's "journal" (written as if the story of Geralt was being told from the future) that said the solution to the problem would prove to be "a poet." Had I not combed through the journal entry, I wouldn't have been privy to this clue (there was no dialog to prompt me, for example). While the clue is easily missed and unnecessary to complete the quest (at least, for the most simple resolution), it was one instance in which I became aware of a deeper layer to the gameworld. Curious players who dig into the story of The Witcher will be rewarded.

...and Eurogamer also played the same quest:

Non-linearity continues to be the driving force behind development of this sequel. A heavily-modified Aurora Engine has been eschewed in favour of a brand new, in-house proprietary system. This has allowed the team to take more hands-on control over balancing, the development of non-linear quests and debugging.

The side-quest we're presented with is a case in point. After discovering the gruesome remains of one victim, deep within the stone ruins of the Vergen catacombs, a detailed examination reveals something embedded within the festering corpse.

At this point in the game Geralt lacks the necessary tools for extraction. So it's a tantalising example of the piñata approach to quest development: a box of delights, filled with unfinished business for the determined explorer.