Precisely as bad as everyone says, but it's also just dull as hell. It's like the slacker kid who waited til 5 minutes before the class project was due to hand it in. In fact, if this had been a student project (or a fan game), I might've been more charitable toward it. It's also amusing how much better "Serious" Sam Stone is at being Duke Nukem than Duke himself; Duke is essentially an entirely unoriginal hack, with zero charm to boot. In fact, DNF may be one of the defining Hack works of art of our age.

It has own its reputation.
The good ideas are parts where you're shrinked at a tiny size. That's it. And they're not even really good ideas. They're much more "less bad" ideas than the rest of the game.

Kudo to the submarine boss. Submarine gameplay is a thing every player loves in every game (it isn't), they decided to conclude it by a boss. It features an attack where he swallows water which drags you toward its mouth. Unfortunately, you have to face him to shoot at him, which prevents you from running aways from this attack. If you rotate to run aways, escape from this attack and get amunition situated at the farthest point from the boss, you won't be able to shoot at him. You have to choose between two undoable bad options : either run aways and do nothing except hoping you have enough time to refill your ammunitions, either shoot at him without enough ammo and compromise your survival. Brilliant.