>>38343001It's beloved because of the numerous new things it brought to the series
Day/night cycles, breeding, new types, shiny Pokemon, new types of Pokeballs, richer lore, etc.
Not to mention it was a proper sequel which allowed us to revisit a lot of old characters and see them in a new light
Then there was the biggest moment for most people being the fight on Mt. Silver with Red
To me it felt like I was surpassing my old self when I defeated him that gave the journey through both regions feel totally conclusive in a way beating the Elite Four and Champions in both generations couldn't quite emulate
Personally I really loved the atmosphere of Johto too
I felt like a proper adventurer scouring the world through mysterious and wild lands
Ilex Forest and its shrine, the Alph Ruins, Ecruteak's Towers, Whirl Islands, the river past New Bark, The Dragon Den, and so much more.
The closest things in Kanto that matched that Mystery were the Cinnabar Lab, Seafoam Islands, Cerulean Cave, and the Power Plant.
In Johto it felt like there was so much more and it had Kanto to reexplore on top of that.
The music wonderfully captured the atmosphere too and I still remember most of it to this day
