It seems if you stop at the selling screen while finishing the day under certain circumstances, the game might freeze. I still hear the sound of the cauldron gurgling, but the screen is black and the screen showing the stats of the finished day won't come up. Encountered the bug on browser version in fullscreen mode.
Edit: I was hovering my cursor over a potion when it happened. It never occured on my second playthrough after reloading the page, it seems, and I managed to actually get the winning ending this time. I like your games, and this one has not become an exception. Amazing work, both you and the artist/animator! ^^