I really love the idea .. and my imagination runs wild
Probably it is to short to change something now but maybe we can share some ideas here?
So first of all why is the moon breaking apart?
I could imagine some different scenarios like a huge man made explosion or some cosmic event.
A man made explosion might be that humanity banned nuclear plant to the underground of the moon and then transferring energy in form of laser beams to earth therefore avoiding the ecological impact of generating the power on earth itself. Now something happened ... an accident? .. and the sub moon plant fragmented 1/3 of the moon as seen in the pictures.
Another potential cause might be an asteroid (iron core maybe?) coming from outer space taking a swing by around Jupiter and (intentionally?) hits the moon with high speed. Not a direct hit but more a near miss just touching the edge.
Thinking about it .. if the moon would be broken apart by 1/3 as in the picture this would be a very fast extinction event. The gravitational effects on tides, orbit and earth rotation alone would be completely sufficient to make the planet uninhabitable in a very short time. Continuous rain of moon fragments would even make things worse and the moon is really big. So expect some things coming down would be in size several times bigger than what caused the extinction of the dinosaurs.
So if the impact would be that large there would be only one chance to survive ... leave earth ASAP. This starts impossible and will get worse every day. Surviving Mars? For a colony somewhere but not on earth you would need at least a few thousand human beings and even if you can play some tricks with bio and genetic techs humans need a biosphere to live in. The amount of resources and technologies you would need to build enough space ships is incredible. So this scenario would be unrealistic if it does not end with the last survivors on earth just being some octopus or bacteria near a volcanic hot spot in the deep of the oceans and the rest a frozen iceball.
Let's assume that the pictures are a bit exaggerated and its "only" a few crater walls and mountains blown into orbit. As the pieces are smaller a lot of them might break apart in smaller pieces which are then falling down into some near gravitational wells ... moon and earth. It will probably create enough stuff to hit both of them for centuries to come. Tidal forces might even create some nice rings around earth. But the continuous rain of meteoroids is what is the most likely scenario. for the game.
Now with all these meteoroids raining down but the main orbit and spin mostly being unaffected what is this stuff composed off ?
We know since Apollo that the moon consists of earth mantle materials. So most of the stuff would be just non organic dust and stones as we have them really everywhere. Why should some stone improve the economy? Maybe an iron core asteroid will bring benefits? Even if most material would be iron this is one of the most common elements on the surface of earth too. Not much of a benefit either. My favorite would be something like graphite where the dust could be used as an lubricant maybe ...
Would love to have a small dose of science added to the scenario, maybe some research questline too?
I would imagine that it would be fun to struggle for survival with meteors coming down in always faster frequency every impact on the map in a random region causing a heat wave in the vicinity and adding to a saturation of dust to the atmosphere causing longer and longer periods of freezing cold winters. It could even be that the only normal temperature is between the impact heat and the followup winter and without impacts you will simply freeze to death.
The other part of the extension I currently have a hard time to make the connection between the Moon event and loosing hope. As of now everything is welcome which increases the challenge because without spoilage its far to easy to create huge piles of food or materials to just wait out for the Bunker to be finished. I would imagine that every failure in defence, every interrupted quest should remove some hope. Maybe hope trickle down continously?
Imho the loosing hope part should be balanced/accompanied with productivity losses. If you start using happiness drugs the people should get addicted causing more criminal behavior and some big loss in productivity. Even now the health system is far to easy. You can treat nearly every sickness in the tent or hospital in a few days without any long-term consequences. Allow for more severe decisions .. injured have a high chance to keep some permanent negative traits which you can only get rid of when they leave. You can treat them for some a small but long time unhappiness factor or let them die for a huge drop which can even result in revolts or civil wars.
Maybe a bit to much on my wishlist but I would love to have a bit less SimCity and more harsh survival.
Really excited ... can't wait to see how it will play out
Kind regards, ...