Linko64: They're entirely different games, Doom 64 has much more vertical map design, deeper looping design. It's not just a port or a small-sized WAD
EraScarecrow: But what really makes it different?
Original sprites, original textures, original soundtrack, original level design, original sounds, original engine with original features including rather interesting (colored) lighting and some new triggers (I think). The 2020 release also has some DSP effects which I don't know if they are in the OG but I imagine they might be (N64 had some decent DSP power to it; and I think they tried to make a faithful rerelease). It has a completely different atmosphere and visual feel to it. There's at least one original weapon too, and at least one new enemy.
I'd call it a reimagined doom that maintains the core gameplay pretty much as-is but changes the tone to be a little less upbeat and more chill/spooky. Soundtrack less metal and more ambience/atmosphere. I think the sounds also have a similar change towards darker/gloomer. I think levels feel more surreal in general, which I always liked in Doom.
Very worthy title in my opinion, and it is much more deserving to be its own game than Doom 2 ever was was (which just looks and feels almost identical to Ultimate Doom, just with an extra gun, a handful of much needed extra enemies, and some new textures).
It's a whole new experience to me, and I'm so glad it's finally here.
With level editors for DooM i recall there were WAD packs to download giving you hundreds, nay thousands of levels, and even CD's with WADs on them.
Yep, but that's just not the same thing at all.