I'm nearing the end of Duke Nukem Forever in preparation for our review (coming tomorrow!) and stumbled across this amazing bug. What you see above is a texture glitch that has made all the objects, items and floor surfaces resemble the shattered casing of a disco ball.
I had a quick check around the Internet and found out that several others are experiencing this visual oddity as well. It's certainly made the level more difficult to navigate, but it's SO PRETTY!
I've taken a few quick photos for you to look at. A couple of people have suggested this was intentionally kept in the game for fun, which wouldn't surprise me at this rate! Either way, it's rather bizarre so check out the pictures!