Setting aside the style, I think you asked for more output — 5,000 words — than your prompt supports, so the model repeated the same details over and over to stretch out the story after it hits the major notes.

Obvious tells are repetitive numeric details: the number of lines of code (mentioned six times!), the number of pages in the manual, the ages of the developers, the age of the game, etc. The narrative itself also repeats, like the Steam rejection included verbatim twice, especially after the Prologue hit most of the beats in the first 400 words.