The Mini Mario Orchestra took a bunch of musical numbers from a variety of role-playing games and strung it all together to create the "Epic RPG Medley." It's not just J-RPGs, as there are some songs from Skyrim and Mass Effect in here as well.
There's a bunch of other videogame covers over on his YouTube channel worth checking out while you're at it.
Here are some comparison shots for the Smash Bros. and Mario Party amiibo lines
1:30 PM on 03.09.2015