Hi! You can find my initial concepts for the characters here on the dev blog, although with the next content update I'd like to do some more refined portraits that will go alongside their sections in the relationship tab. In the long run I would like to incorporate more visuals into the game but that's probably not going to happen until I'm actually done writing it.
Is it not currently downloadable? It would still be the same index file that runs right here in the browser, I don't currently have the resources to package it as an independent application (and probably wouldn't want to while it's still in such an early and unfinished stage.)