Well it looks like it will be just as moody and scary to play as doom4 with a few twists that bring it out as something special. The open ended feel and the AI changes should make for quite an experience. Take a look at the videos on http://www.2kgames.com/bioshock/html/download.htm as they show not only the sheer class of the engine, but also talks through some of the special stuff.
[screenshots from the bioshock site]
According to Wikipedia http://en.wikipedia.org/wiki/Bioshock#Engine the engine is another derivative of Unreal's work (was Vengence2 based on Unreal2.5, now Unreal3) - it is rather stunning!
Setup Hammer to work with GMod finally - not a smooth process, but it works. Have to work out how to launch it from within hammer (that would be nice).
The Million Masterpiece (I'm at http://www.millionmasterpiece.com/profile-463283 and it is fun to see the comments arrive - the pic seems to cheer people up :-)
DAZ - started on a simple piece with the intent of some photoshop postwork.
Here is the basic piece before any 2D work:
[journeytime = 2.5 hours]