Update. The best metriodvania platformer is missing from the options.
As of this post I have to say it's Shantae.
But Super Metriod and Zero Mission are very close.
What I like about Shantae is they weren't afraid to change up controls and abilities completely each game. Same formula, but unique mechanics each game not just slightly tweaked mechanics.
Also they've done a great job of making the adventure much less lonely than the other franchises through some very entertaining non-playable characters.
Lastly each game is deliberately telling a story with a much longer arc than any one game can contain.
The Shantae sequels feel like they exist because there is more story to be told, not simply more money to be milked.
I can't believe I waited so long to play this game.
And for all the good I've said about Shantae, Ori and the Blind Forest is every bit as good!
The classics at last have some very worthy current gen competition!