It is not a hub. Not a main menu. Not an online shop.
People die in Bastion! They get tricked, take wrong turns, and fall victim to industrial accidents.
When characters haul the Treasure out of the expedition site, and slog their way back through Deep Country or the Underground, they don't get to switch off just because they're in the city.
Run it like a dungeon. Draw a map, fill it with odd stuff, punish mistakes.
When they go off-grid, roll on tables and make stuff up.
EVERYTHING IS HERE
NOBODY KNOWS WHO'S IN CHARGE
EVERYTHING IS COMPLICATED
People are unhelpful.
Places are difficult to get to.
Things run bumpily.
Finding and receiving treatment from a doctor is an adventure.
Going shopping is an adventure.
Getting the train to the library is an adventure.
No downtime without decisions.
No switching off.
Everything is the game.
The game is always on.