Overall production and quality-wise, Vosmug has seen a significant improvement over the years since Xenotake. The animations are fluid, the game feels smooth, there's even some proper 3D cutscenes. The audio design, mix-and-matching the soundtrack to an appropriate atmosphere of the game is also something noticeable.
Unfortunately, as a game, I have to say that it feels like a step back somehow. Vosmug wanted to experiment, or perhaps simply got tired of complex gameplay causing complex bugs, and did this one as something of a point and click adventure game - to keep the pretense of a "game" instead of it being a "visual novel". All of the "adventuring" pretty much boils down to "find thing A, bring it to place B", and I could NOT shake off the feeling that I am, "playing" something that is basically in fact just a visual novel. There's very few moments in the game where you can actually lose and have to reload.
By far the best part of the game is writing. The plot is interesting, the characters are compelling, I was thoroughly invested from the very start in finding out what the player character's motivations and goals are. The plot also takes many unexpecting twists and turns, I caught myself with an "oh fuck!" moment at least three times.
The fact that the characters are compelling is kind of the game's detriment to me, because, well, most of them basically serve the purpose of being rape bait. Finding out their complex emotions and motivations and then empathizing with them conflicts with the enjoyment of any rape content... which is pretty much all the content there is in the game.
But maybe that's my personal skill issue or something.
Slight spoiler:
The ending was somewhat of a disappointment. Singular, because you just unlock more of the same ending as you meet the proper conditions. It also has a bit of a twist in it, and the very finale is, of course, bittersweet. Which is fine in its own way, but I feel like it needed some more epilogue/closure.