Basically, for the past several month I have been working in a team of three people working on a VN. There is only one artist as part of the team tho, who does everything art related basically. She has been awesome so far, especially when it comes to background (at least the quality satisfies me), but now that we moved on to the characters, something feels off about them, and I'm not even sure how to express this. So I'm looking for feedback.
The quality of her art is good, so not complaining about that, but I'm looking for a feedback style-wise. This is the first sketch of hers and of our first character (neither protagonist nor antagonist).
To me it just feels like the characters lack 'volume', 'liveliness' and look 'too 2d'. Please let me know what you think of art, and also if you agree with my comments, let me know how can I express more specifically which parts she should fix for the style to suit the VN more.
Disclosure: The artist isn't very familiar with anime/manga/visual novels, so this might be part of the issue. Also, in case this matters, the VN is going be in genres of fantasy, action, detective, mystery, city fantasy, supernatural, and a small touch of religion/philosophy.
Black&White version

Coloured version

Background to check the style





