I like what I played of the demo so far, but I'm worried the game might fall victim to feature/scope creep, with five different playable characters and different stories for each. Maybe after a certain point past the intro it won't matter as much, but I can't say I look forward to splitting up multiple saves for five different characters on 18 save slots.
My suggestion for the devs would be to have all the content visible on a single playthrough. After Harumi's intro, it should switch to Reiko's intro with less tutorial stuff involved, then go onto the next, so on and so forth, until you actually have party members together and the game just keeps going from there.
Reiko's first scene feels out of place. I get that it's to contrast Reiko being an actual sex-haver and Harumi's shy awkward virginity, but downloading a game based on the concept of "magical girls with dicks" and having one of the first scenes be... "regular girl riding boyfriend and during the sex she finds out he's cheating on her" doesn't quite leave a good impression for what the rest of the game is going to be like. Considering at this point in development the player is allowed to pick whatever character to play as first, it also means it might be the exact first thing they really see in the game too.
I don't mind the dudes so much in the public masturbation scene, even if I'd prefer minimal-to-no dudes in ero-scenes in the game going forward, because at least it's still involving the reason why people are interested in the game in the first place: futanari.