Actually, Brutal Doom 64 is awesome. I don't agree with you guys saying that it kills the mood. In fact, it adds a lot to the original game, improving controls, gameplay and visuals.
Firstly, controls. You play it with GZDoom, which is a source port that is available both on PC and Switch. This source port allows you to play Doom with any controller scheme, including the one of newer FPS games. You can use left analog to move / strafe, and the right analog to looking both horizontal and vertically. You can use D-Pad to change weapons, and trigger buttons to shoot. Combining with Brutal Doom 64, you can aim and shoot enemies on specific spots and having multiple ways of killing monsters, such as head-shot.
Secondly, gameplay. Although they've made some specific changes in the original game, BD64 is mostly very similar to original Doom 64. The same atmosphere was maintained, the weapons' gameplay were mostly based on classic Doom (no new COD-like weapons just like on original Brutal Doom) and the original maps are mostly there (except for a few new areas here and there). On top of that, BD64 adds new features that was cut due to N64's cartridge space. Some monsters were included, such as Revenants and Masterminds. And last but not least, there's even multiplayer support where you can play both on cooperative and deathmatch with up to 64 players, something that was also cut on the original game.
Finally, visuals. GZDoom allows you to customize graphics in many ways. You can use pixelated graphics just like on vanilla Doom, bilinear filtering just like on a N64 game, and even use advanced HD filtering that upscales graphics for higher resolutions without losing much quality. You can freely choose which one suits you better. On top of that, there's some new visual effects, such as animated skies, lightning system, fog, and brightmaps (monsters eyes glowing in the dark).
Of course, the original Doom64 has its value, and it's a awesome game that's finally being re-released nowadays. But Brutal Doom 64 isn't bad. It has a value of its own.