I mean like, compare a … hub and spokes style immersive sim game, to any given open world game.

With an ImSim, you often get planted into an area, with a single or multiple main quests, and a whole bunch of essentially discoverable sidequests… and, when done well, those optional sidequests significantly affect how the main quests play out, and may give you different options for how to approach or conclude those main quests.

Then, onto the next hub/spoke section.

ImSims are not typically associated with literal huge spaces… but the spaces they do have tend to be well interwoven.

But also, they’re not strictly linear in the way of like … an FPS campaign/single player mode usually is. Sure you can have the literal levels be maze like, but theres usually only one entrance and exit.

ImSims open up the conceptual field of a given linear sequence of levels, by allowing totally different play styles to yield signifcantly different experiences, and often the additional mechanics they do this with are more than just combat… social and exploratory play can be rewarded or punished by altering the narrative itself.

There are often entirely optional, missable ‘sidequests and submazes’, basically, even in a typically smaller amount of literal space.