On Twitter I have Tweeted a few times about something called Fallen, which is a project that I want to make that features for example Oppi in it. Like it mentions in one of the pictures, There's no heaven or hell, but there's only Fallen, which is basically if the afterlife had a world like ours, but for the dead.
I want this project to be a mod for Doom II (since I originally wanted it to be a mod for Quake, thinking about changing it to Quake II, but I'm more familiar with Doom Builder and Doom 64 Builder and idk if I would make a mod for something like Quake), and have Oppi to be like a companion for you (Thinking like Kazooie from Banjo Kazooie, but instead she punches the enemies while you're shooting them).
I don't want to make the game like heavily based on religious and specific mythologies, otherwise people would find Fallen to be a big Doom knockoff. I mean in Doom Eternal, Heaven is now a thing in the Doom franchise (at least some levels that takes place there), and that's why I don't want to make the whole "3 worlds" cliché (heaven, earth and hell) and make a more unique world instead. But there are going to be a few references to these in the universe, like Greece and Norse mythology for example and even religion. But not in depth, that's Doom's job.
I'm currently working on each part of Fallen's world, and so far I made 3 (Going to update if I come up with more today).
I honestly would like to see some opinions about this, about what I should change and what I should work on more.