I liked everything up to the point where Angler gets the phone and starts talking to Otsoa. The narration, visual presentation/art and character work for them prior to that is stellar and I really like the exploration of the quiet longing and loneliness of deep sea creatures. But Otsoa themself felt a little superfluous to me because their conversations with Angler felt a little stilted and overly drawn out. The only important thing they really did was give Angler a name and then be removed from the story. I was much more interested in Angler's internality and the exploration of the deep ocean than I was in Otsoa. I also don't feel that it implemented the theme well at all or really had a wolf. Otsoa of course technically meets that criteria by being a wolf, but in practice their nature does not matter and any nocturnal land creature would have worked just as well for this. The references to folklore are also sparse: It's only the name Otsoa and the other possible options they give. None of the really affects the plot.
However, the art here is really really good, and I like what was done with the lighting. Having it be dark for the majority of the VN really sold the idea of the crushing and bleak ocean. It also offset the moments with light, particularly the end, and made them much more impactful.