

Symphony of the Night is, in fact, the origin of the term Metroidvania but not in the way you might think. Castlevania pre SotN was a very different series with none of the elements associated with “metroidvania”, so people started calling SOTN a “metroid-vania” derogatorily, as a Castlevania that was trying to ape Metroid. The term had staying power for the genre because what the fuck else are you gonna call them, it was before slapping -like on everything was popular but after calling stuff “clones” had fallen out of favor. No, “search action” will never be a thing. And you’re not just gonna call them Metroids because that’s one specific series. So after future Castlevanias had Metroidy stuff in them, it became a genre name.
Hollow Knight also felt like it was in dialogue with the Souls series, because the Souls series iterated on a ton of Metroid’s mechanics in a new space. So it took Souls’ “what if Metroid mapping, lonely mysterious vibes, backtracking and key/locks, but slower paced 3d combat and the keys aren’t weapons” and went “Ok but what if we used the lessons we learned from you to improve the Super Metroid formula that inspired you?”