[My review has NO spoilers. If you're thinking about playing this game, avoid spoilers if possible!]
I got the original version on Gameboy when I was a child and spent so many hours in the game world trying to complete it.
It has always been 1 of my favorite games out of all I've ever played.
It took me years to finally beat the game on Gameboy, I had to wait to grow up some more before I could solve some of the mysteries on the island.(I was born in '87)
Still to this day even for adults I would consider the game not an easy run through, which is a good thing in my opinion to help you immerse in the surreal game world, unfortunately with internet and low self control of people today, they probably just look up everything when they're stuck.
Try to never do that if you play this game because what you're really getting with this game is a unique experience, and once you complete the game the window of opportunity for that experience is over and you can never go back to feel things the same way.
Intentionally take your time, explore, interact with people on the island at various stages of your adventure, and delay completing your adventure as if you'd rather just become a permanent resident there than even finish your quest.
I bought the 2019 Switch version the day it was released, even knowing it was almost entirely the same game just in beautiful 3D.
The 2019 version is amazing.
I'm not sure if it has the same degree of surreal mysterious vibes to it as the Gameboy version back in those days but it's of unbelievable quality and made me love the game even more.
I would recommend this to every Switch owner!
I think I will always consider this Nintendo's "Magnum Opus".
EDIT: There is a secret ending, you can only see it if your game has 0 deaths on the save file. I think that's important information for anyone before they commit to this game, and more of a reason to take your time and power up before running through all of the battles.