I just beat Shadow Warrior (The original 97' FPS)
I wouldn't say it was as good as Duke Nukem 3D. Duke Nukem 3D had very varied levels. (The entire second episode of that game took place in outer space. Whereas the rest of the game took place in cities and stuff.) It's weapon selection was also kind of lackluster and it was pretty short in general. The game only has 24 levels, compared to Duke Nukem 3D which had 30 vanilla, and fully patched contained 41 with the addition of the 4th episode. The final level even just recycled two of the bosses from earlier in the game, and ended with a surprisingly easy final boss.
But it was an enjoyable game nevertheless. I might check out it's two expansion packs while I'm at it.