Although this has some cool ideas, mediocrity in graphics and gameplay stands out. Not as bad as the media is saying!
Graphics
First of all, the engine and graphics of Duke Nukem Forever are pretty outdated, no reviews exaggerated on that, they were pretty on spot.
It looks like 2K picked up the game from where it was left in development and applied some make up on the textures that were standing out the most (character faces, guns, items, enemies, etc.) but left most of it in the state it was (pretty ugly [!] for today's standards [!] ). Looking at myself in the mirrors of the game was particularly a bad experience that reminded me how old the graphics engine was.
There's almost no physics simulation in this game as well, some veeery basic gravity stuff but overall pretty weak too, which goes to further prove how old the engine is.
Gameplay
Well, I expected more from it. I hate it how they scrapped a couple of old-school mechanics that kind of made the game unique for me, and what I loved in old-school games. Mostly the lack of overall secrets in the level (except for non-useful ego boosting secrets) and the fact that you can only carry 2 weapons now.
Managing ammo on Duke Nukem Forever was one of the funnest aspects of it. Omg! I found some ammo for my Devastator, should I just blow it all in the first guy I see or should I save it in case a bigger enemy comes later?
It looks like a lot was streamlined to make the game "not difficult" for people who play Halo/CoD/mainstream FPShooters nowdays. There's veeeery little puzzle solving (compared to old-school Duke and even Quake) and very little frustration in terms of weapon usage. If a given boss requires an RPG to take down effectivelly, they'll give it to you and infinite ammo so you don't mess up.
Don't take me wrong, the overall gameplay is much better than most reviewers make it seem, and you actually have to think in some parts of the game (unlike for most of CoD/Halo/Crysis where it's all streamlined and you just have to do things however you want to) and that's probably what pissed some reviewers. Having to understand how to take down a boss instead of just shooting it makes people don't like games nowadays, they want the "hollywood experience" that CoD made us get so used to.
Overall? 6.5/10 for me, more due to gameplay issues than graphics' or sounds' issues (although that obviously still counts, this could never get a 10 even with perfect gameplay).
It's not a HORRIBLE game like most reviewers are making it out to be, its gameplay is actually pretty damn good. If it had pretty graphics and higher production values be 100% certain they'd give this a 9/10.
Check most user reviews (the ones who wrote it, instead of the kids with 10 years old who play just on their xbox and never knew old-school gaming - Duke Nukem, TMNT, Contra, Golden Axe, Quake, Doom - and who only care about graphics and having the game show them how to beat it instead of actually thinking), they'll say pretty much what I said.