The Witcher 2: Assassins of Kings has been revealed a few days ago, thanks to the leaked footage from CD Projekt RED's promotional material for the game.

GRY Online questioned Tomasz Gop, Senior Producer, who uncovers some additional details about the project and explains the footage a bit more. Here's a snip from the interview:

What engine will be used in The Witcher 2?

The game does not use the Aurora Engine anymore. We developed a brand new engine dedicated to creating games with the design and features we love (basically the same concept as in the first Witcher but everything done much better, smoother and with some significant improvements). The new engine is fully scalable and, well… kicks ass;). We believe it will let us avoid all bottlenecks we came across during development of the first Witcher. Exact engine specifications, features and name will be revealed after the official announcement.

Read the rest here.

Oh and you can stop worrying, the trailer didn't feature the Witcher's "real voice" (like I said, it was obvious they voiced the footage in a hurry and without professional actors).