[hightreason]

The length should fit the content... For example, Crysis is around 3 hours if I remember correctly, but it feels too long because there is naff all to do in the levels - some games, like Blood seem to short because of just how much there is in the game. When I play DNF it will take me at least a week as I am going to go around pressing the spacebar on everything and looking at every little detail with the volume up as high as it will go.

Edit: Perhaps the game WILL take forever to beat, maybe they used a Text-To-Speech type engine for Duke that generates random quotes based on keywords attached to parts of the level and the levels have a random generator like F-Zero X but better.