I noticed the game does not seem to save progress when refreshing on Firefox. This seems to be because of my browser locale rendering the date in a differnt format than expected by the code.
This seems to be an issue with a difference in formatting between the saved game state format, which is formatted as M/D/Y, and the date it compares to from the "today" element, which is formatted Y-M-D, according to my browser's locale. These are compared in the game.js file.
