I really like the game so far. I play using NVDA screen reader on Windows, and it work very well. Thanks for creating this cool game.
There is no explicit, built-in key to quit the game. I assumed that users would either reload the page or simply navigate away or close the browser window when they were done playing, but if there's a convention for quitting browser games from a screen reader context, let me know and I'll see if I can implement it.