The thought of dungeons appearing all over the globe and civilians somehow getting tasked with exploration instead of the military... (It sounds ridiculous because it kinda is, but also in places in like America and Japan you'd have large swaths of the population that would be fucking demanding access like that to the point where any politicians that didn't acquiesce would quickly find themselves out of a job; which is the most terrifying thing for a politician.) Just makes me think what an economic boom that would be for America. Civilians would need more ammunition, firearms, knives/melee weapons, NVGs and thermals, IFAKs and other equipment. Civilians would also have a common goal to work toward in the dungeon and fighting something other than each other. Materials from the dungeon would allow it to be a profitable job and make a new market and economic opportunity...
In fact, the biggest problem might be too many people wanting to go into the dungeons and kill shit that there might not be enough dungeons...
Kami-sama, if you're there, please make dungeons appear in the U.S. Japan can have some, too, in rural places.