Well, that's obsessive. For those who truly can't let go of Super Smash Bros. Melee, there's a mod being made for Super Smash Bros. Ultimate. Much like "Project M" before it, the mod is being developed by a modder on Twitter named NyxTheShield, which he has dubbed "Project NX". He's already teased some of the mechanics so far on a couple of posts, as you can see below the character moving and changing positionings at a faster framerate like they do in Melee. This is basically a solution to the idea of having the gameplay like the 18-year-old title but still have a massive roster with updated moves of the current version.
Palu Movement pic.twitter.com/kzNMRNnp9r
— NyxTheShield (@NyxTheShield) January 11, 2019
The obvious guess as to why it's being made, aside from nostalgia, is to re-create Melee in custom tournaments with the updated look and feel. But, Nintendo may not be a fan of it since it's not clear if the mod affects only Smash Bros. multiplayer, or if it treads into other parts of the game as well so people could use the new mechanics to cheat their way to victory. In any case, if you absolutely need to play a Melee version of Ultimate, there's hope on the way.