Your art is incredible, but I'm not really a fan of VNs, so I'm not going to comment on the gameplay. I'll keep my review limited to the art, aesthetics and sound.
The style is coherent and vibrant. Characters are expressive with an exaggerated style, which suits the aesthetic. The colour palette is appropriate, but I feel that the contrast on some characters is too strong (harpy girl for example). I feel you could tone down the contrast on some characters a little to bring them into line with the whole cast. Lines are clean, but there are some issues with the plaid design on some characters. The plaid pattern should follow the contours of the clothes, you know this because you did it on some images, but in many others it looks like the plaid was just overlaid flatly, which makes it look uncanny. Strongly recommend you redo most of the plaid clothing to follow contours and folds.
Some backgrounds look really good, while others seem to be computer generated (not AI). In some scenes this creates a dissonance between the characters (who are hand drawn) and the background. I think it's fine for now, but consider this for the future.
Sound was fine, nothing spectacular, but nothing wrong with it. Audio adds another layer to video games, I do recommend perhaps investing a little bit more time into understanding sound design and how to use it to add additional dimensionality to your game.
For my final thoughts, good job and making a game with strong art direction. I feel perhaps your art skills are wasted on a VN and think you can probably tackle something more ambitious for your next project. Well done, looking forward to the final product.