Hi! Author here... actually it does use unicode (which we'll use to mean non-ascii at the moment, even though ascii is part of unicode (pedantry, pedantry)) for the starfield at the moment, those are braille characters so that it can have "smoother" and more fine grained movement of the stars. The frame around the game also uses non-ascii characters. However I'm planning on adding two modes: one that uses
no unicode characters and is pure, and one that uses more unicode for a larger variance.
I tried being moderately conservative for the moment because I'm not sure which terminals support what! (Admittedly the recent addition of starfields in git master stepped away from that a little)