At least without warning. I was typing to a friend, went to hit backspace hit F12 by accident (wasn't really paying attention), and the game just closed without warning.
When I went back to reload the game, the game thankfully still had a record of me in my dungeon, but it froze and never loaded!
Quite upset at the moment. At the very least make it Alt+F12, because just F12 is too easy to hit by accident. Add in a "Are you sure you want to quit?" with it for confirmation on a Shortcut.
F12 saves a screenshot to your desktop... that's an interesting crash if it closes the game for you every time.