I'm definitely missing something. I read through the rules, and there doesn't appear to be anything prompting when you roll a die, except for certain miracles... which only happen after you roll a die. Furthermore, the map appears to serve absolutely no function whatsoever except as a potential reminder of some of the things you've done already. No interactable objects are placed on the map and there is no map movement. I don't see the point of it.
Oh yeah for sure lemme clarify! You're going to roll a die before every miracle you perform. 1 "Round" of the game is the loop of "Roll the die, choose a miracle, perform the dice effects or text on the miracle to advance fiction, then move onto the next roll." Every miracle you perform should have a die roll associated with it.
In terms of The Map, there's a far more popular and better designed game called "The Quiet Year" that was the inspiration for this game. Effectively, you use a deck of playing cards instead of a die and prompts for each card to interact with the map. Honestly, you might try playing that before this to get an idea of what the Map is supposed to be doing? They have this quote on their webpage: "part roleplaying game, part cartographic poetry." Cartographic Poetry is such a difficult concept to get across, but how I personally use it is to come up with a backstory for a world I want to play fiction in? Basically using a game to create a world for another potential game (or just the meditative activity of worldbuilding with rules for randomness).
Anyways, all that is to say that you're super justified in your confusion! Hopefully that sort of helps?
So is this a turn -based game, where each turn consists of choosing a miracle to attempt, then rolling a die to discover the results?
Still not entirely sure on the map, but maybe I'll try to read the rules for The Quiet Year and see if that helps.
[EDIT]: I read the rules for The Quiet Year. TQY seems to be a narrative TTRPG that uses the map as a visual aid to remember what decisions have been made and what actions have occurred. I feel like even in TQY, this could easily be a textual list, and even more so in God Die as the game actions have no impact on the map.
Furthermore, actions in TQY are semi-random; in God Die, they are deliberately chosen -- the only randomness is the die result. Because the population starts at 1 and you can always choose for the population to never reach 0, the only actual loss condition is 20 Floor. This makes the entire game "roll a die until your Floor hits 20." Why would you not choose every miracle to be "decrease your Floor to 5"? The only reason I can conceive of is not wanting to be bored, because the game is, in fact, incredibly boring. The main issue with this game is that there aren't any rules besides a loss condition.
I would suggest swapping that order around: roll the die, then choose a miracle. It's subtle, but the die result should inform what you do, as opposed to the other way around.
You're correct, rules as written, the Population reaching 0 should always be a voluntary event here. But I do have a suggestion: when you roll anything that says "Sacrifice" (so like a 2-12) that's a bad thing happening, right? So that's where you can create the fall in population, or various other negative outcomes. Sacrifice means something bad has to happen, and there's only a certain amount of systems to interact with in the game (Population, Heroes, Floor, Landmarks, and Testaments). I usually defaulted to decreasing population on a Sacrifice because it's an easy consequence, and the kinda only way to actually fail with population. The reason that's not in the rules is because you could just fail turn one and lose. I wanted you to be able to build a bit of a buffer before the failures really start to pile on late.
As for the boring part, sure lol! Design philosophy wise, I always like the definition of a game from Bernard Suits: "a game is the voluntary attempt to overcome unnecessary obstacles." So like, everything in this game is entirely unnecessary to interact with outside of the Floor eventually reaching 20 from rolling failures :) That's really the only part of this that's a game, otherwise I'd say it's a 90/10 split on story-making to game, and that's not for everyone! I appreciate the feedback!