Campaing idea: A only set at night campaign

Hi everyone,

I wanted to write a campaign set in one city and its surroundings but in a world that is constantly at nighttime.

Without considering the apocalyptic circumstances (which I already considered in the story), the idea is to make economic systems based on light sources and better focus on time passing.

I'm mainly in doubt whether to apply a "roguelike" system of progression, where PCs starts at point A (the main HUB) and need to go to point B or complete a quest and if there's a TPK, they return to point A with the same or new PCs (considering hypothetical checkpoints if the campaign is too long), or a more "expedition" type of structure, kind of like Monster Hunter, where they still need to return to the main hub after some time has passed. I may also go with a more traditional approach, as always; I just don't know how much this kind of system can work in a TTRPG.

The inspiration for the campaign is obviously Bloodborne.

It may sound like a campaign relying mainly on combat, but truly it is not. I still haven't built the actual city since I want to read the PCs' backstory first.

For now, I just wrote down why everything is always at nighttime and the circumstances of what would happen if the world went into full darkness for long periods of time.