Thanks for the feedback! When your village center gets destroyed the aristocrazy (you) gets wiped out and so there's no one left to rule your people! On a serious note, we are going to make it more obvious when you're under attack. There is an icon popping up on the minimap, and a sound is played, but it doesn't seem to be enough. At least you'll be able to wall in your base to protect your village center in the next update!