Duke Nukem 3d's story was set in the near future,and more specifically in 2007,something that we get by the in-game calendar that we find in a room at Hollywood Holocaust.
In Duke Nukem Forever,we learn that its scenario is set 12 years after the events of DN3D,through a dialogue between Duke and Holsom twins.
Since the events of Duke Nukem 3d happened in 2007,the year that the events of DNF happen should be 2019.

But in DNF we get in the Duke Nukem Museum,where it is stated that the events of Duke Nukem 3d happened in 1996 instead of 2007.
And here we got the first WTF moment.

But if the events of DN3D happened in 1996,then the events of DNF happen in 2008.

It's messed up.
