Keeping track of booth screens at once wasn't that hard for me either, but I can imagine increasing the number of text messages you receive (maybe in big waves and by different persons?) could foster the feeling of overtaxing.
Eventhough adding different persons to the story might take away the personal and close mood your game has.
However these are just my suggestions, I have no doubt there are many different ways you could take on expanding this project and improve it even further.