The non textured style is actually very pleasant (I think it's intentional) and done very well. It has a nice contrast to the coloured objects that you are meant to interact with, and allows for minimal UI while still making it obvious what the user has to click on.
I did not get that far into the story, but the notes littered around the map were a cool addition that was interesting to read and again a very non-intrusive way to guide the user through the experience.
Great game overall, awesome work!