Having played it and OPP, I can say I very much enjoyed it and look forward to the game's full release. It is very rough and bare bones right now, but it's a demo, so that is nonthing to complain about. Just means it has a lot of room to grow from a very sturdy foundation.
I greatly enjoyed the tool usage and the need to explore and interact with multiple routes before finding the correct one through trial and error. Especially anything that calls back to OPP, where knowledge from that can help with this game. Unsure if it is simply not included yet, but I was hoping that using the blue potion at the cauldron would allow for a possible ending where you could use your new ass to defeat the skeletons by outdamaging them, the same way you can use the trapped chest to get past the gawkers.
Another thing I enjoyed (while others may not share this with me) is the bad endings; I'm quite a fan of getting descriptive text detailing the endings our characters meet.
A great example is the ending, where you face down the skeletons while under the effects of the bells, causing you to become very milky, leading to your character becoming tired from the burden of their swollen chest and the milk healing the skelly boys, (which reminds me of a very similar ending one can get in Litith's Lair, which may have inspired this one of your own.) I know it is a touchy subject, as a lot of people want soft, uwu, everyone happy and horny, nonthing bad ever happening. Just these perfect blissful "safe" horny scenarios.
But in my opinion, having bad endings and not everyone reacting cheerfully IS fun (and I'm very glad we get a choice in how the character reacts to transformations, rather than being locked into always being horny). Having some dialogue for them to react to the transformations, along with the current character portrait that we can see ourselves in from the third person, would make it even better!
I believe that having bad endings, unhappy characters, and not always being this bubbly and always-horny style of character offers more creative routes for your writing to develop and, as such, for gameplay too.
I want to pop if I'm inflated
I want to fall if I'm big.
I want to explode if I'm milky and get backed up with the stuff.
Now, these are just my opinions and my own tastes, and at the end of the day it is up to you and what you want this game to be. But with this being slightly more action-oriented, rather than purely trying to keep track of details like OPP, I think this could be a fun and safe place to explore ideas like that. I mean, we already canonically die and get bought back to life at town, so why not include some ending where your big milky breasts get poked by some spear-welding goblin and go pop. I think for Inclusion's sake there could be some type of tick to avoid those endings if people don't want to see them.
But in my view, that makes for a much duller and shallower game.
I am really looking forward to this being finished and released. I believe there is only one possible pathway to beating the demo at the time of posting, but having multiple possible routes would be good to include for future levels, tho I'm sure that when we get more classes and items brought in. There'll be a veritable spreadsheet of possible pathways you'll have to account for on your hands.
I hope the best for you and the artists that you are working with, and I will happily buy this game day one once it comes out.