Inb4 Capcom Cease and Desist.
What made Megaman Legends such a fantastic series that it has created such a fan following? :o
It starts with the first game being pretty well done on its own and a decent base for the start of a series. An the follow up tripling the efforts of the first one and following up in unexpected ways that really stuck with the fanbase. Now days though anything they did isn't to special. Large bosses, cell shaded look, a functioning camera, a targeting system, and loads of customization. Things that are easy to find now.
So it the games pretty much have story going for them, which in a Megaman game you usually aren't around for. They had a more cinematic feel compared to others in the series, with OK voice acting to boot. No megaman 8 "dactor whairy", or X4's "WHAT AM I FIGHTING FOR!!!" An again while the first one laid it all out it was the second one that really bumped it up. Following up with a lot of answers, what happened to roll's parents, megaman's past, and everything in the pudding! All led to a cliff hanger with megaman stuck on the moon, and earth about to be under attack.
To note literally every question got answered, outside of what the hell the motherload was. Thing is the answers ended up damning a few characters to things like memory loss or body snatching. So their plot threads aren't really finished either.
An alternative way for some people to see it is, look at what resident evil 4 did for resident evil when it came out. :/ Through gameplay and story telling, coming off the side scroller games legends was quite a jarring experience.
Anyway that is best I can explain it outside of saying go play the games. Legends 1 can be emulated fine, but 2 is the problem :/ mid way through the game there is a water section which is really cool. However it plays with how the game works in stupid ways making it hard to emulate. An forget about the side game the misadventures of tron bon which last I checked had text issues. x.x