I've made a theme for this game, to get it run this shell command (you only need this once, so you can use pastebin run) after running the game for the first time:
pastebin run ywaiAf9dNote that after you use the theme, you will need it every time you run the game, or else it will complain.
This theme would be a lot cooler if it affected the actual gameplay screen, but currently it does not. (Hellkid, is this a bug?)