It's a solid start to a vn, Squishmeisters artwork is fantastic as always, and the writing so far is pretty good.

I'm uncertain what engine this game is running on, it's clearly not renpy which is curious considering it isn't doing anything you wouldn't see there, and it's lacking in some of the built-in quality of life features you'd see in most vn's. Namely, it's options menu is lacking, there's no options for font sizes or types, window modes, skip options, etc. The save and load feature seems currently non-functional, saves seem to populate a temporary thumbnail then cease to exist, assumedly not writing any actual data considering the shortness of this demo. Really my biggest desire out of this functionality wise though is being able to control most/if not all of the game with only the mouse. I tend to relax when playing VN's, and prefer this mode of play, currently the esc key is mandatory for exiting menus, that's really it.

The writing is currently nice but a little plain? It's not flavorless but the characters thus far are kind of simple, focused squarely on the fetish with little other motivations or desires typically. This works better in a comic like Ayano due to the heavy visual element, keeping the fetish front and center, and engaging. Via it's constant visual stream of information, incorporarting unique situations to enjoy the gain in various ways. But in a VN where artwork is often re-used and cgs are not ever present, I think the writing would benefit from the characters having a bit more going on. Keeping the writing largely focused on the fetish material is good, fine, but give the characters more quirks, hobbies, just some flavor really. Akane was actually my favorite for more or less these reasons. She's pretty funny! And her crisis over "cursing" Hibiki is cute.

 All this said, the fetish content itself is again, competently written, Hibiki's last late-night binge is a good scene, and definitely left me wanting to see more.

The presentation is largely really good, as mentioned Squishmeister's artwork is lovely as always, the girls are cute, and expressive. I'll refrain on any comments on the backgrounds as you've mentioned they're largely placeholder. The UI however is also visually pleasing, being clean and easy to look at. Stuff like transitions between scenes, skips in time, and the little animations that do pop up are all good.

Considering I don't know what will change and what won't, I don't have much to say about the music/sound design, but it generally felt fitting and never distracted from what was happening. So, if nothing else it all felt like it was cohesive.

Overall, I think this project is really promising actually. I know I spent a while being relatively critical on the writing, but being a vn I figured I'd give it special attention. It really isn't bad, I just want to see it be as good as I feel it could be. It's all nicely written with no major grammatical or pacing errors (that I noticed at least.) It's obvious that it had work put in. I'll definitely be keeping up with this project and I look forward to what you guys make!