Is the writing good? It's inspired, definitely. Is there an indication of plot? Sort of. It's obvious that the dev wants there to be.
There are indications of characterization, world building, and more. They're all very promising. The problem is that this game is the very definition of Dev Alpha. Not Player Alpha -- Dev Alpha.
Allow me to explain: a player alpha has what one might consider playable content to a reasonable breakpoint. The end of a story arc or character arc, in this case, as either of those elements are core features to this game. Furthermore, the erotic mechanics of the game should be sufficiently present and accessible to the player as well. In short, the core game loop needs to be evident to the player, and effectively all intended game features or mechanics represented in some way.
This game doesn't have that. This game is inspired, indubitably, but it isn't a v-slice. Its core game loop is kind of all over the place and isn't player friendly in what can be experienced and what can't. It's clear the dev is iterating and incrementing, but they're doing so in a variety of areas rather than completing at least one core game path/experience for the player to assess what the completed game would be like. Assuming all mechanics are present, even if they're just stubs, it's Dev Alpha, technically.
But that doesn't mean "the fun" the dev intends for the player can be understood.
The dev created a compelling and complete prologue, but it's largely a passive experience compared to what they intend for the rest of the game.
I'd advise the dev to finish an Act 1 or Act 2 arc with some of the day to day, one Act 1/2 chain discovered during that day to day (e.g. farm), and one Act 1/2 arc with Dahlia or one of the other NPCs. Then it's a player alpha and better bugs as well as user experience feedback will start coming in.