Here's what's happening in my fort.
First, an Ettin suddenly showed up, to great fanfare. At which point I realized that over the past two years, I had been so fixated on trying to make sense of the various new mechanics that I had neglected to seal my main entrance with doors. And, my primary mason having died in a ceiling collapse (which was entirely my fault) a few months before, my stoneworking industry had been lagging and I had no doors. I frantically tried to set up a wall and build some wooden doors while the beast smashed through a floodgate (flooding my farm) and obliterated by trade depot, but I couldn't get it done fast enough.
I set up an emergency burrow in the back of the fort and send my military to guard the main entrance immediately! Except of the six of them, something like four are asleep and one more is like a million miles away, so I have one speardwarf and like twenty dogs duking it out with this Ettin. Except I never managed to get my military to do one frigging day of training because of how broken the new military currently is, so even the one who's fighting is a novice. At one point he landed a single punch (I don't know why, since he had a spear) and instantly shot up to Elite Wrestling.
Eventually, the Ettin goes down (mostly to the dogs), and the brave soldier goes off to the hospital with a broken wrist. A dwarven caravan arrives, but my depot is gone, so they're just sitting out on the edge of the map. I send people out to rebuild the depot and get that wall built, but like ten seconds later, goblins suddenly appear! I desperately recall my civilians and send what remains of my military back out, but things are looking grim. The ranged goblins distract the 2-3 soldiers that actually answered the call while a goblin axeman with a halberd blows through the front line and starts butchering everybody. Everything got kind of hazy after that, but at one point, I could only spot three soldiers: one was unconscious, and both of the other two had had their weapon-holding arms chopped off. Then a second squad of goblins appeared.
My fortress is pretty much done for at this point. I set up a new burrow recalling whatever survivors I can find to the underground crypt...most of them can't make it past the halberdier in the dining room. Then I draft about 3/4 of them into unarmed militia and station them at the ramp. My only hope is to order my last surviving miner to tunnel miles below the surface of the earth and seal my surviving dwarves down there to start a new society of subterranean molepeople while the dreaded goblin halberdier cuts the meatshields down in droves.
Fortunately, the goblins turned their attention to the distant caravan at this point. All of them except the halberdier go off to engage them and get slaughtered. Apparently the halberdier hears about it and flees from the region. My population has gone from about 56 to 27, with almost all of my most skilled dwarves dead (apart from the legendary armorsmith, who just barely survived, being taken by a strange mood and running upstairs like five seconds before the last goblin left).
I'd try to rebuild anyway, except my mayor/manager/broker/whatever else died and I can't refill the positions because of the bug.