Fusion was also my first, but I played it on the GBA. I still have my original cart for it and will sometimes play it on a modded GBA. Although having it on my hacked 3DS is also convenient too.
As for Zero Mission and AM2R, both are fun. Zero Mission is a bit hand holdy for the first playthrough, but if you explore a bit or look up guides you can ignore the waypoints and sequence break the game. AM2R is fairly linear because of the nature of Metroid 2, but that doesn’t detract from it being one of my favorite Metroid experiences.
GNU’s Hurd was supposed to be this iirc. That clearly hasn’t gotten far and hasn’t been progressing quickly.
You should. He’s done very entertaining stuff around Raspberry Pis and other fun projects.