Hi there, I'm a solo indie dev and I've recently released Nuumonsters to Steam and itch. Since my Steam release less than 3 months ago I've updated it 16+ times.
I'm currently working on an in-depth story for the player to explore, and (trying) to get an iconic OST made for the game. Currently I have 60+ monsters, 70+ different moves, several towns and areas, almost 100 Trainers and NPC's, battling, inventory with lots of items, and fishing.

Next I'm adding customizable, secret/hidden bases, and then I am going full ham on implement an awesome story. But when I look back at games like Pokemon Emerald, the story isn't exactly the first thing that comes to mind. The game is such a joy to play even long after the story is beaten, and you often find yourself avoiding the story because you'd rather do your own thing out in the open world.

So to restate my original question, what makes monster tamer games so great? What kind of things should I add, or focus on, to really bring out that nostalgic feeling left in the past. I'm told by many people that the game does a great job feeling nostalgic, but I believe that's mostly due to the art style. I'm really proud of my art, but I want it to be more than something pretty to look at. I want it to feel like an awesome adventure people can look back on years later and have those same nostalgic feelings they had with other classic titles.

Any tips are appreciated, I'll try to respond to each and every one of you, thanks for reading!