I did like the fact that there were many different hells with punishments based on the religion of the person. Like say your religion doesn't believe in hell then there wouldn't be one. Also like the religious currency, that one was kinda funny.
I loved the variety cause even if every religion believes they are the one and only, what matters is the heart, so this was a good illustration
Not sure if I get this right but I think there is also hell for those that don't believe in any religion. There was one mentioned—forgot the chapter—where they talked about non-believers being punished too. So far, as what I understood, the hells are shared and the specific religion's hell is just automatic but if it goes to over-occupancy, then they can just send them to another religion's hell, same thing I guess to Non-believers or religion that doesn't have hell (although I doubt there is one?). Basically, at the end of the day, the bad is punished and the good is saved, the one who died in the wrong time gets reincarnated.
Oh there are actual religions that believe God is not as a cruel to create a suffering after death and we are destined to just cease existing. But about the non-believers punishment, we see that only the bad ones get the hell and the good get a straight card to heaven. Which I loved too (hate religions that say you are automatically going to hell only cause you aren't one of them)
The reincarnation one was so cool too, they don't have to go through the afterlife process if they didn't get to live their own lifespan because the living world is so unfair.
I think a lot of this story's world-building is based on Korean Mythos' and syncretic religions' description of the afterlife as a convoluted bureaucracy. Not sure how often manhwas are inspired by that particular aspect of the culture since this is the first one I've read that leans in heavy to it but there are probably others. You do see Western authors taking this approach (ie. The Good Place, Terry Pratchett's writing, Welcome to Hell) but I think in Korean culture there's an actual folklore precedent for it