I like that there is no outright explanation for the apocalypse and they sprinkled some mystery breadcrumbs. So far I have:

• Mt. Fuji erupted
• rogue military AI
• talk of radiation

The timeframe is also a mystery for me. Depending on whether MC has “visions” or “memories”, it’s unlikely that the decay has progressed so far in what little time has passed based on her age. Now, if it’s not memories but visions of the past it’s a different story. But in that case she might just as well be in the distant future. At least that would explain why there is so much decay and why she has an android sidekick. The only question in that case would be where and how the sister from the pictures fits in. But maybe she and the sister are androids as well, with the sister being one early models from before the apocalypse and MC being a 200 years later model developed in the shelters.

I’m intrigued to find out.