I opened the gates for further immigration, because i wanted to see a siege again (my military forts are fully generational and take forever to pick up population, exactly because of slow attrition eroding away the married couples). Since Galleywheels had its first ambush by the end of year two and they never stopped since, the goblins dutifully sent a siege shortly after we reached 80 beards. However, it was a horrible disappointment: a single large macegoblin detachment with a speargoblin leader riding a giant olm. They all got squished in two shakes of the bridges. They barely hit twenty gobbos.
In autumn, i got an interesting visitor: a demonic diplomat, posing as deity of the humans. "Beware its fire!" - it ran into the autumn ambushes and scorched the surface. The dwarfs didn't appreciate the kill-stealing and wouldn't deal with a demonic abomination, so opened the second entrance path, the one that _can_ let units through alive, but has its own security measures installed. Once the demon was inside, the bridges at both ends of the path were raised and the spikes activated: nine "upright spikes" installations, one or two each of bronze and steel, driven by a minecart repeater. It took a bit of juggling to get the visitor to pass over the spikes while active, but on the third go, it got spiked and stayed spiked. As trophies, we confiscated its trousers (over 700kg) and socks.
Losses of dwarven life: one brewer stabbed in the head as thanks for detecting a goblin thief, one child torn apart by a vulture (eventually walled over the outside area, because vultures just wouldn't stop), one carpenter who decided he had to clean the squish trap while active. I've since disabled cleaning on everybody. Dead goblins: about 150. No military, but i pulled a few dwarfs out of fatal cleaning jobs and off hunting in the face of the enemy by turning them military and giving them a station order. I also sent a makeshift two-dwarf wrestler squad to kill a vulture that'd gotten inside and wouldn't leave or die on its own.
I also got the path layout sorted for the "firecontrolled" minecart area defence: a single-minecart, single-windmill installation using diagonal movement to cover three firing lanes:
Every grid that's either built track or a door (on top of track) can be hit by the minecart. It self-regulates, opening the doors for action and temporarily deactivating the rollers on the return track, so it can keep cycling intermittently as long as the fire signal is active. It would be activated by creature-sensing pressure plates on the tracks.
In other news, another moron decided they had serious business in the smash trap to attend. I've constructed a citizen-triggered pressure plate with adjacent hatch cover to hopefully stop this kind of idiocy, since there's no way to strictly forbid dwarfs from pathing into it - legal path is required for goblins to enter, after all.