I fundamentally dissagree with the term "metroidvania" because Metroid and Castlevania are different. Both are what I call a "side-scrolling action platformer," but Metroid gives the player powerups to encourage them to explore their environment, while Castlevanias powerups focus almost entirely on combat. Therefore Metroid includes "adventure" in its genre, but Castlevania does not.

I never got lost in a Metroid game, but I also have a pretty good ability to remember how I got somewhere. Metroid does a generally pretty good job making nearly every room memorable and unique to help players not get lost, and Metroid has mostly included a map to help players as well. If players are still getting lost, IMO that's just a skill issue.

But I understand what the author is trying to say, and they are right. Actually getting lost is not what they mean, they mean level and game design that lends itself to encouraging exploration by trial and error. Level design and game design that shows the player some impassable wall early and then when they get the ability to pass it later on, leaving it entirely up to the player to remember. Backtracking is a mandatory staple, if a Metroid game has no backtracking, especially for item expansions, then it is not a real Metroid game. Making the player be the one to do the exploring and not holding their hand is crucial to a good Metroid experience. This is why I consider Metroid Fusion, Other M, and Dread to be among the weaker Metroid titles. All three have an obvious, forced always on hand-holding mechanic that you don't find in other Metroid games. Like the developers don't trust the player to actually be smart enough to figure the game out.