"Main menu" button just removes you from your on-going game without saving.

[Morthor]

If you press the Esc key and click main menu, which I did accidentally when wanting to change settings, the game just goes to the Main menu without saving your current progression. It's extremely frustrating. I lost quite a but of progression i those 10 mins from last auto save, since I play in the fastest mode all the time. Please add a prompt to save or something similar on that button.

Thank you