Takara no Jin (treasure jin) is going to be a very deep game with
many levels
storyline
and original characters
it not one of those games with no story and only one level. It's be like you're downloading a whole game from eshop
If you have to resort to multiple parts perhaps you could ask Kamui if you could use the program she made which allows you to open different games from one program(the other programs have to be in the same file) which means you couldmake it so users would be able to access multiple parts from one program. Plus you can release each part as it's finished.
Just make sure you upload the program Kamui made(After some small adjustments so it fits your game) and then release the other parts(Just make sure that whoever downloads it knows to put it in the folder they put the Kamui program in) and if it's a really big game you could make chapters(each chapter could consist of X amount of parts)
And each chapter would have it's own folder and each folder would have it's own Kamui program since the Kamui program can only play the parts that are in the same folder.
I already thought it might be too big and already decided to make it in parts. But i don't think i need to download her thing because there are simple commands that can already do that.
However, I'm somewhat knew at this thing so it's kind of slow.
So anything you could teach me would be a big help.