> Do players really build all that, or does the ingame AI make those decisions?
The AI controls the dwarves, the players issue directions. The ASCII is a bit hard to read, but there are plenty of graphical tile packs. I like Phoebus right now, but Mayday & Ironhand's graphics are also nice. Look for something called the "Lazy Newbie Pack" and then at the tutorial threads if you ever want to get started.
Also, you can lock doors and such. It won't stop building destroyers or thieves (kobolds), but everyone else will just sort of walk up to it and wonder what to do. Dwarves can only destroy doors and other stuff when they go crazy, which tends to happen if they're unhappy enough.
> Jeez, the fortresses can become pretty massive.
Actually, that's pretty small, these days. This was also done on an old version that had maybe 40 levels to dig through. New ones are more like 200 unless you change settings. Oh, and there's a magma sea at the bottom. Magma is very Fun(TM) so more than a few players (including me) have constructed gigantic pump stacks with ~100 iron pumps powered by perpetual motion devices that pump magma up near the surface where it can be used for traps / forges / Fun(TM).
That game is a succession game (everyone plays for one year, taking over for the last person, so they may be surprised ... and appalled ... at how people before them have been running the fortress).
The comment about dwarf bread being a lethal throwing weapon is, sadly, true. But everything is (was?) a lethal throwing weapon: the throwing skill was completely broken. You could throw anything (and I mean anything) that you could actually hold at someone and have it be deadly once you had enough throwing skill.
Anyhow, the jokes get a lot funnier when you understand how the game is played. For example, there once was a weaponsmith who ran outside to grab a sock someone had dropped outside. He got ambushed by a kobold who had a copper knife. The kobold attacked him and cut his finger a tiny bit, then ran away. The weaponsmith hobbled back to the fortress, making a big deal about his minor injury. Then he decided to faint from the pain while on one of the weapon traps near the entrance. Normally, dwarves can walk over their own traps just fine. But if you faint? You get chopped to bits by the trap. At least he's not in pain now. I set up a coffin for him.
As for the comments about the elephants, they used to be deadly (as were carp... yes, the fish... it's now an in joke). So he trapped one of the elephants who had been killing folks in a cage trap, then traded it to the humans. Due to yet another bug, any animal that had killed dwarves could be "tamed" and yet it would continue to attack dwarves who believed it to be "tame" even as it was killing them and who wouldn't fight back. So, that elephant they gave them was dangerous...