The story telling was great
Ugh no. The entire story is lacking depth. Is there even much of a story?
the gameplay was very solid.
The game felt like it was just trying to impress others with the physics engine. Physics weren't that common back then and it seems like Valve really wanted to show that off.
it's still fun to play.
I had more fun in Half-Life 1.
Duke Nukem, however, sucked because it tried to take the old game's humor, then threw in some "lol this game took long" jokes in, then half assed that with some pretty mediocre gameplay thrown in.
Did you really expect a serious Duke Nukem game?
The "mediocre" gameplay as you called it is still better than Half-Life 2. The AI in Duke Nukem Forver is a lot tougher and smarter than the Combine AI in Half-Life 2. The AI in Half-Life 2 is scripted to miss their first few shots and they are also scripted to have long periods of hesitation between shots not to mention they are much weaker than the pig cops. Even in Hard mode you could kill a combine in 1 hit with a revolver.
Duke was a mess, HL2 was not.
If you say so. Duke Nukem Forever is a much more faster pace, has a better AI, with better weapons, better vehicle missions, etc.
Half-Life 2 was just basically a way to show off physics as you couldn't already tell with the gravity gun, explosive barrels, picking up items, lame physics puzzles, etc.
For each physics puzzle in Duke Nukem Forever you may notice how much Duke either makes fun of Valve or a valve game. The Duke Nukem series seems to do this a lot. The original Duke Nukem parodies the side scroller Megaman. Duke Nukem 3D parodies the 3D shooter era. Third person Duke Nukem parodies Tomb Raider. Duke Nukem Forever parodies Halo, CoD and mostly Half-Life 2.