I loved the demo a lot, the characters are very endearing, the story is really intriguing and the art is breathtaking.
While I am glad I found and played the demo, I think this will be it for me since I am quite monogamous haha. But I 10000% recommend it to people who are not or don't mind romancing both at the same time, the game is really enjoyable and even more for poly people I'm sure :)
Edit, 3 days later lol: Sooo, this is kinda funny, but I went back and replayed everything (first time I played was at 4am, so I didn't digest all the details). Somehow, I started appreciating a lot more the relationship between Violo and Vivere, I had definitely liked it the first time, but I came with a new understanding after the replay. Beforehand, I had gone into the game having already made up my mind that "I'm monogamous, so I probably won't like the romance as much", which I think ended up hindering my first playthrough. The second time, I went into it with a more open mind, and I'm so glad I did. I ended up not really being bothered by the polyamorous aspect at all, I actually love the kind of dependent relationship that comes with Viola and Vivere. For the longest time they have only had each other as a source of companionship and support, they're two complicated souls that are cut off from normal socialization and cling onto each other.
While in the beginning I would've preferred they had separate routes, I can understand (and I actually like) why this is just not an option, they're dependent lovers that care for each other more than anything in the world, an outsider just can't get rid of it. I like that they truly care for each other's opinion, even if at first it looks like Violo dismisses Vivere's. I like how only towards a mutual interest in the mc can the relationship truly happen, I've read the creator's comments and I completely understand them better now (the whole "both or neither, but never either"), it just really makes sense.
I also like the dynamic that the mc brings to the table. Violo and Vivere have only had each other for the longest time, neither of them is really knowledgeable on healthy coping mechanism or other social aspects that come with living in a society. I like that the mc can sometimes give their two cents and help them with internal conflicts and worries (even trauma, thinking of the scene with Violo and his 'father'). I also appreciate how organic it feels when Vivere is warming up to them, it did not feel forced, and I love that not at any point of you having caught both of their interest made them feel less like a couple themselves. But at the same time, the mc does not feel like an intruder at any moment, maybe a tiny smallish bit a the beginning when Vivere hasn't yet warmed up to you, but after it just feels like it makes sense, y'know? Honestly, the writing on the relationships caught by by surprise a bit, it's just that good.
And so, apparently I'm gonna stick with this game for a while lol. I'm glad I gave it a second chance and got out of my comfort zone (the whole poly thing), because I've found two of my new favorite characters in a good while, I grew to love them so much more, especially because of their relationship with each other.
Also, this is just a small error I found during my second playthrough, but the morning after the mc goes to the dungeons down the stairs and Vivere comes to visit there's an "image not found" error. It's not a big deal, but I thought I'd mention it in case it might help haha. 
