The website of Spicey Horse says that they are still looking for people with experience in the Unreal 3 engine, so my guess is that the game will be running on that game-engine (although this is by no means official).
Personally, I can't wait! I honestly never expected this to happen. Since American Mcgee's Alice recieved good reviews but never hit the public very good. They even cancelled the announced PlayStation 2 port that was announced earlier, so my hopes went down. But now it actually seems to become reality. The article didn't say a whole lot, but it included one piece of conceptart and the news that they want to release it for PS3, XBox 360, and PC.
Here's the conceptart:

Source: http://www.americanmcgee.com/wordpress/ ... ce-sequel/
