The lack of emotion I feel while playing through Cave Story's plot surprises me

Cave Story got updated on Steam with a bunch of improvements, so I started playing with my boyfriend. I've gone through this game like 3 times already, never got the True Ending because I lost my save before the true boss twice, so you can call me a larper if you want.

As you can probably guess, I find this game pretty fun, but the one thing that always leaves me unsatisfied is the story. I'm the kind of person who I'll go through any kind of media for the characters, but playing through Cave Story all I feel for them is... nothing.

This game is chock-full of characters deaths, yet even as an 11-year old playing through this game the first time I didn't feel anything for any of them. Characters only say 10 lines at the start and ending of each area, and they only ever address the main character when they want to ask you to be their slave. No one has any character development, no one is more complex than their character's description, what did the game want me to care about? their designs?

The first time I played the game, my reaction when anyone died was just "Oh, ok". And when I finished, I got the Bad Ending, however I didn't even consider that I could've possibly saved some of the characters, nor did I feel the need to, because why would I? Why would I care if such a gripping character like Professor Booster lived or died? All he did was appear, tell me to do chores and then die, was I supposed to care more about stopping his death than Blade's or Toroko's? Characters kept dying non-stop I just assumed the game was cynical like that and so was the ending.

On that note why am I supposed to care more about Curly than any other character? because she is a c-cute g-girl? She has like 15 more lines than the rest of the cast and that's it, I don't know her for real.

You are probably thinking "Dude this is just an old platformer, it's not that deep", and normally I would agree with you, but this game is seen as one of the mothers of indie games, other great titles like Undertale take a bunch of stuff from it. Besides Cave Story isn't THAT old, there were already games with amazing stories in 2004, and the game got a ton of re-releases, none of that effort could have gone into fleshing out the characters more?

The Wikipedia page for the game even says "It received widespread critical acclaim for many polished aspects of its design, such as its compelling characters, setting, story, and gameplay.". So what, am I the only person not able to see how deep and complex the story is, and how charming and likeable the characters are?