This is a crazy doujinshi from 2013, which I found completely by chance in the bargain rack at a Suragaya in Denden Town. I'm pretty sure I found it on the same day as I went to some other comic event, and only had a very quick browse in passing.

Anyway, it's unusually in English (mostly!), and is made by AC Galaga... who, according to some included ephemera, had a baby on the way so just "crapped out something quick" in order to have at least one new comic at whatever event this was sold at.

His "quickly crapped out" comics look better than my actual ones.

It appears to be an original, not based on some other work. Though Rie and the other characters seem to be assumed to be familiar to the reader. Perhaps there was a whole series of Rie books, though they aren't mentioned on AC Galaga's website. One of the characters is "Space Monkey", which I doubt is related to the cool bar in Kitashinchi... which I really need to get back to, one of these days.

Yeah, that's right, website. A proper, navigable, ad-free listing of his comics (well, some of them), laid out in a logical order and accessible without having to register for anything. Why can't more doujinshi makers do that? An X(児Twitter) page is no use at all, especially if you don't have an account on there.

Also there's a silent(ish) backup story that somebody else wrote.