I feel like this is way more confusing that it needs to be.
For starters, mangaka forgot to have her explain exactly why the world would supposedly end.
And did they just forget the hacker that was randomly walking around their ramen shop to order takoyaki instead?
And this chapter started with a flashback that was left unfinished almost entire chapter for no good reason. And then when it tried to finish it, it did not actually explain anything about it.
And so on.
It's slightly too early to talk about what and why the world ends (spoiling it early would actually ruin a lot of things).
The hacker guy is a key character in volume 2, and this is the only chapter he does not appear in since his debut in volume 1.
The original author is Jun Maeda, Na-ga is the character designer, while ZEN is just turning the anime into manga, so there are a lot of cut-offs and changes in character lines, but overall, it still keeps what the original story wants to show. Therefore, the flashback at the beginning of the chapter alongside what happens after wasn't explained clearly due to page limitations, which also caused some confusion. I'll post a chapter today to explain some notable changes in the manga compared to the anime version.
You can watch the anime (which finished even before this manga) to understand more of the story.