UPDATE: i played the game a second time, and the flashing box didn't appear, so it might just be something to do with me refreshing the browser; i'm not sure. one other note, while i think of it: the sound effect that plays when text is being displayed is a bit loud compared to the rest of the audio. you might want to adjust that because those sounds can be distracting.
i forgot to mention this before: i really liked the colour palette you used in the game. it completely enhances the mood and suits the setting (time period) very well