No way to save game progress

I haven’t been able to find any way to save my game progress. I managed to get an option to save one time (I think by using cmd-q to quit), but never saw it again. Now cmd-q just quits the game with no prompt. Escape brings up an in game menu, but all it includes is options to make in app purchases, no option to save the game.

guyincognito2 about Duke Nukem: Manhattan Project