Apparently it's very heavily influenced by 90's-style shooters. But I don't think it's an old-fashioned Doom clone like Serious Sam or something to that extent. But there are a lot of hail-backs to 90's level/puzzle design. The first level is a remake of the Cycloid boss battle from Duke3D. The level of interactivity that is trademark to Duke is also reported to have been present.

I guess we'll find out just how much of an old-fashioned shooter it is. I think it'd be a great breath of fresh air with all the grimy stuff nowadays. And hopefully it will spawn a new era of classic and FUN FPS's. An article by Yahtzee (of Zero Punctuation fame) on the impending release of DNF:

http://www.escapistmagazine.com/articles/view … e-Nukem-Forever