Gearbox in Amsterdam showed a sneak peak of Duke Nukem gameplay. They also stated the following about the demo release.
"The demo is going to go out to everybody, yeah," Gearbox VP of marketing Steve Gibson said. "When we put Borderlands out this wasn't even possible to do or contemplate. So that's kind of difficult, but yeah, the demo is coming out for everybody.
The feeling is that we want people to feel that it's real. We want people to know that 'holy crap, they're actually making plans.' It's kind of like, Borderlands: Game Of The Year is great and by the way, these guys are also working on this, and it is real, and we're trying to get that association, that proof.