What a pleasant surprise!! Probably my new favorite Metroidvania. (unless you count Cave Story? Which I personally don't)
I had started to think I might just not like the genre all that much--this was very much a "lets see what all the fuss is about" kind of playthrough--but it confirmed my suspicion that any negative feelings towards it were just my contrarian instinct kicking in in response to oversaturation.
When these games are good, they're real fuckin good!!