Exploration without hand holding.
NPCs that will miss-guide you.
One of the first games with a meaningful day/night cycle.
Origin of the best songs in its franchise.
Multiple endings dpendant on your performance.
The game is popular one to get shit on for being to difficult and NPCs giving clues that end up to nothing along with clues that are useful. The only regular critisism that I find valid is the lengthy transition between day and night that compleatley breaks the pacing of the game.
This is the apex of metroidvania from before metroidvania was a thing.
I will always recoomend this game with the caveat that you should play it and stay away from looking things up online/in guides since that removes the entire point of the exploration and figurering things out aspect of the game.