So I'm chillin' dorf-style, minding my own business, diggin some ore, makin some doors, engraving walls, throwing parties, etc.
A VILE FORCE OF DARKNESS HAS ARRIVED! **SIEGE**
Uh oh, that can't be good.. but, I should be okay, all my doors are buttoned up tight, there's no way they can get in.
Dogbert McSavageBreath has been struck down!
OH NO
All of a sudden all my guard dogs at the entrance are dead and there are 6 goblin pikemen running rampant through my fortress. I checked all my doors, they're all locked. Checked my walls, no breaches that I can see. No ramps that would allow them into the keep, and my stairwell to the cavern is also blocked off from the main fortress by 2 more locked doors. All doors are stone and none say "taken by the enemy".
How could they get in? What did I overlook? Fortunately, after reducing my population by 30% and killing almost all of my war dogs, apparently they got bored and left. I manged to kill 3 of them. They're still in the Units list, but now they're outside the walls and don't seem interested in getting back in. What should I look for as far as defensive weaknesses go? I could have sworn I had all my bases covered, the previous 8 or 10 rounds of ambushers never found a way in.. can vile forces of darkness jump over walls or do they pick locks? Even if so, wouldn't there be a door somewhere on the perimeter that says "taken by the enemy"?