Not sure how. Most I can say is that the menu text is a little small. And the choices could be aligned to either side, considering the characters are usually in the center of the screen. And the cursor and name text are misaligned when choosing your name.
Otherwise, there are custom text containers, separate choice containers for selected and unselected choices, and not much other UI to speak of. If judging by mainstream game standards, sure. In a place where most games use the default Renpy settings, including that huge ugly black textbox, it'd be pretty hardcore nitpicking.
