This might genuinely be one of my favourite h-games by the time it's finished. This is very promising, though I do have a few suggestions.
First, some more growth sound-effects would be real nice. The "bwoomp" is nice for something immediate but it would definitely be better imo if there were more gradual, slower soundeffects for right before and during growth, besides the "bwoomp". There's also currently no soundeffect at all for instances where you only have to add in the ditzy potion, and it feels like there could be one.
Some sort of basic royalty free calm background music would also add a bit to the immersion if you ask me, similar to how RPGmaker games tend to use a bunch of royalty-free music that comes with the program. Would also be an excuse to work audio volume settings (sfx and music separately) into the game.
My most major suggestion would be some kind of freeplay mode in the future, even if an unlockable one, similar to Cowtastic Cafe. Somewhere where you're free to make any potion you want and use it or anyone with no penalty, or even use any cursed items on NPCs not meant to normally get them.
Additionally, freeplay where you can just do anything you like could be an enticing as an unlockable to be honest, because as it stands I kind of just don't care for potions that don't do anything for my fetishes (lips potion specifically) so I don't bother adding it even when I know it's part of the correct mix, but if some kind of permanent unlock in freeplay was tied to doing well in the main campaign mode it would be enticing to actually play correctly.
That, or at least a simple fetish toggle so players can just adjust certain potions to not do anything visually when starting a new game. Could reflavor their descriptions as... literally just changing the flavor of the potion or something, as far as text is concerned.
As it currently stands, you're kinda incentivized to do things incorrectly if you want to make all the girls have effects to your liking.
Speaking of freeplay, I feel like besides a mode like that, the game could very much benefit from a non-campaign mode where you just get random customers and events and try to keep going indefinitely. But all of this is more for later in development, since a lot seems like placeholders right now.
Some hints are also kind of unclear at the moment. I couldn't figure out if there's any way to uncurse the thief after cursing them in the current build, or a way to uncurse the stone statue, or a way to fully fill up the slime jar (because I tried getting all of them and paying close attention in a 7-day playthrough and the NPC still says she needs a few more), or if the two cursed necklaces have literally any use right now.