Personally If you wanna make stuff more difficult I'd rather he buff the current civs. Getting sieged by six civs at once isn't so much difficult as "well gotta stay locked up for another 3 months."
Unfortunately (or, perhaps, fortunately for some), there isn't really a way I can make a civilization that is able to overcome this strategy. Nothing can break down drawbridges or walls, and flying creatures will only fly over them if a path already exists (it usually doesn't, because that's the whole point of a fortification). I'm going to let Toady do his thing with the military arc before I attempt anything drastic. In the meantime, I'm nerfing bog trolls a bit more to make multiple ambushes a little bit less challenging (though they're still very, very challenging). Don't get too comfortable though - those of you who haven't seen a voidwalker annihilation force because of a low population cap are in for a rougher ride this time. I nearly shat my pants when i saw them show up at my fortress of just over 60 dwarves, but that's what too much wealth will do to you.
I haven't been unlucky enough to run into their most dangerous units yet, though.
Anyways, the idea is sort of to force you to either fight or withdraw. If you fight, you hold the above-ground resources, but lose lives. If you wall yourselves in, you need to go to the caverns. And trust me, this mod puts some nasty stuff in the caverns. Those devourer silk webs don't make themselves. Maybe you'll do a little of both - maybe if you dig down, you'll progress technologically and gain the upper hand over the forces besieging you. Or, more likely, you'll die. You can hold out for a while with walls and drawbridges, but it will halt your progress. If you want a baron or a duke or a king or even just more migrants, that means that sooner or later, through ingenuity or raw power, you'll need to hold the surface. The tech tree updates in the future will give you even more avenues through which to mount your defense. This first installment offers a small taste of what is to come.
If you dig even deeper, you'll ... never mind. I'm not telling you. When you think you've conquered it all, I'll just let it show up. And don't bother looking in the arena, because it isn't there.
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Dwarf Fortress is, in my opinion, best described as an epic tale generator with varying levels of user input. LFR is designed to make each of those tales even more epic.
LFR is about fundamentally raising the stakes of Dwarf Fortress without changing any of the things that make it already so enjoyable. The ultimate goal is that you won't get "bored" anymore. Instead of sitting on a heap of goblin corpses, lauding yourselves and letting your citizens grow fat and old, you'll need to fight for every inch of your legacy. The bog trolls want your stuff. The lizardmen and goblins want you dead. The voidwalkers will do anything to prevent you from reaching their level of technical prowess. Sure, there are the meowkin and nephilim and elves and men who will help you, to varying extents, but to obtain their help, you need to help them get to you. Your race is besieged on all sides by forces larger, more numerous, and more advanced than your own. They will drive you from the earth, or they will drive you deep underground, where even more savage threats lurk. But with this risk comes reward. With desperation comes opportunity. You must hold the deep to hold the surface, and only through constant struggle will you create anything worth engraving on a wall. Even if you somehow prevail, the attacks will continue on all sides until you fall or your computer explodes. Everything you do will feel more important.
In that way, I don't see fortification or "withdrawal" as a bad thing at all. I see it as a natural step in the evolution of a successful fortress. You fortify to buy yourself time to innovate and advance so that you won't have to fortify anymore. Even if your current dwarves are safe, you cannot interact with the outside world if you shut yourself in a hole, and there is so much more glory to be gained from that interaction. No one will remember you if they don't know you exist. There is so much more glory to be won, so many more legacies to be written. If you're a real dwarf, that's motivation enough.
Dig deeper. Invent. Create. Research. Advance. You must do these things or you will do what countless others have done before you - die in isolation, leaving little more behind than piles of rock and ash. Is it more exciting to read - or, through DF, experience - a story that ends with an impenetrable, but isolated fortification, or the twists and turns, mishaps and breakthroughs of a society that flourishes because it refuses to die even in the face of impossible odds? I don't think I need to put up a poll for that question. Rather than atop the bones of goblins, your civilization will be built with the bones of your heroes who will lay down their lives and legacy for a chance to preserve your race for one more generation. Your graveyard will be littered with memorials to dwarves, each with a different role in the tale.
An alchemist who gave his life to the study of materials, bringing about the discovery of ether.
A swordsman, who took up the first ethereal weapon and held off the forces of the lizardmen council while the unarmed civilians retreated behind the walls to begin the siege.
An engineer, who devised the trapped corridor that would break that siege.
A miner, who struck orichalcum whilst hewing out the trap chamber.
A machinist who took the new metal and created the first training dummy.
An axe master, who trained for years on that training dummy and saved the fortress from a threat from below.
This is all possible with LFR - and I assure you, there is more to come.
The Voidwalker Patriarch Obliterator bludgeons the Auxiliary in the head with his (-*glistening voidshard cudgel*-), shattering the skull through the *steel helm*!