I'd like to use something like this in my current kingdom, I love the idea of using mechanisms to help my defense, but the 100% effective ones are boring. The thing is, the entrance to my fortress is not conducive to animal pastures... Getting grass to grow would be a major
construction project (we are talking about years of game time probably, and my sanity. The first pasture I can do - the one at the front to attract any wandering enemies. But I can't think of any way to grab the enemies' attention again once they've fallen through the hatches. They'll just roam around aimlessly once their path is interrupted, no?
At this point I'm considering just having the hatches open to a pool of lava, but then my army wouldn't have much to do. The other downside of that is on the off chance a goblin dies out in the wild, one of my gnomes will go running to steal his stuff and die a fiery death
I really wish there were more ways of differentiating between friend and foe... There are so many fun things I could do with lava if it wouldn't end up killing my gnomes, too.