What happened: When I was returning from the settings menu, I inadvertently clicked "return to main menu". This instantly brought me back to the main menu, causing me to lose all progress with my city.
Expected behaviour: there would have been some warning that all progress would be lost, and/or a prompt to save.
Steps to reproduce:
start game from tutorial,
complete tutorial and continue to build city,
open in-game menu
enter settings menu,
return to in-game menu,
select "return to main menu".