Pretty good
I came across this series while looking for dungeon core books and, being a fan of a similar series, thought I should give this a go.
This is the first short episode of a system apocalypse story. The main character, a somewhat-sleazy young man named Aaron, is turned into a dungeon core. He then builds himself a dungeon and gains power from luring adventurers inside.
Writing quality is about average for self-published KU. There are a number of errors and undesirable quirks, such as missing or incorrect punctuation, run-on sentences, missing words, incorrect words, inconsistent acronyms, singular-plural mismatches, incorrect use of "lay", unanchored and ambiguously anchored pronouns, problems with tense, and so on. There are some little inconsistencies here and there, too.
The narrative is written largely from Aaron's point of view, and is fairly informal, with swearing and other typically informal structures in the prose. The prose is this fairly similar to some of the dialogue, but it works quite well. Dialogue is reasonably consistent for the few characters involved.
There's less attention to detail and less creativity than I'd expected, but what's here is a quick and easy read. There's a single explicit intimate scene of, let's say, dubious consent.
Overall this is pretty good. It's not as good as the much longer-running Lewd Dungeon series, but it's worth a read regardless.