I couldn’t find a concrete answer for this. Attempts to recreate the art style of this game correctly have failed, as seen on posts on Reddit. In particular , in almost all Reddit posts made by users claiming to draw in the art style of this game, the art style doesn’t resemble the actual art style properly.
Just looking up pictures of it on Google images, it’s a detailed artstyle with a rather unique shading style, one that I’d consider to bear some similarities to comic book art styles, but not quite the same. Namely it seems to use multi-banded cel shading for the characters with areas of black in specific places. That’s just a super quick summary from an artist based on skimming through some pictures of the game. I think I’d find it difficult to recreate the style convincingly because there are more fine factors to the art style than the ones I mentioned here.