When the shooters moved from 2.5D sprite-based (Doom 1&2, Duke Nukem 3D) to 3D ones, something important was lost: restriction on performance many that no longer you could fight hordes of enemies, because computers of the day couldn't display them all fast enough. So, enemies got fewer, but tougher, and no longer you could experience the same sheer carnage as fighting hundreds of imps at once.
It was quite a while since I last played a 3D shooter (likely, HL2 Episode 2), so I don't really know if there is something out there that has a similar feel to good old Doom games.
The newest Doom released in 2016 brings back that onslaught in a modern 3D engine. I forget the exact name but I think Mount and Blade had a lot of enemies on screen. It’s a medieval combat game. I’m not sure if Devil Daggers counts because it looks so primitive it might be an engine running 2.5D.
It's so much faster paced. You feel powerful. Weapons feel real. Horses have real inertia. It's more arcadey, but that's the premise. It's just plain brutal fun.
Give it a whirl, and make sure you choose The Olde Knight or the Steppe Prince. And please reply if you do try - it's a lost masterpiece that the original mount and blade should've been
Yup, that is exactly what I wrote in ~99 about Doom, that compared to modern games of the day (Q3, HL2) a lot had been lost. Besides the hordes of enemies, openness of the levels, and many other things: http://strlen.com/maps/pnf_columns.html
It was quite a while since I last played a 3D shooter (likely, HL2 Episode 2), so I don't really know if there is something out there that has a similar feel to good old Doom games.