Redefining "complex", sandbox gaming at its best.
"Soon, Master Elf, you will enjoy the fabled hospitality of the Dwarves! Roaring fires, malt beer, ripe meat off the bone. This, my friend, is the home of my cousin, Balin." ~ Gimli, at the gates of Moria.
What you do in this game is emulate the deeds of Master Durin, lord of Moria. You are sent along another six fellow dwarves armed with nothing but a few picks and axes, and enough food to last a couple months. From there, it's your task to manage to turn cold stone into luxury halls. From simple walk paths to royal dining rooms, it's up to you to survive from the first winter to whatever terror you awake by digging to deep.
"Moria... You fear to go into those mines. The dwarves delved too greedily and too deep. You know what they awoke in the darkness of Khazad-dum... shadow and flame." ~ Saruman, speaking of Gandalf.
And just in case you are wondering; yes. There are Balrogs. And Griffins. And Titans. And Goblin' sieges. Humans. Elf caravans. Undead. Rain. Snow. Floods. Magma. Kings. Nobles. Horses. Armor. Dogs. Cats. Crops. Bees. Towers. Baby dwarves feed with beer, and what not. Think of it, and it's probably there.
That's precisely where this little jewel shines; in a bit more than 23 years of gaming, this is the first time where I get to have fun making a world from scratch, from simple tasks like harvesting a crop inside the halls, to design and operate the irrigation system used to water it. (Levers included!). I even knew of some guy who designed a little CPU using channeled magma. It's incredibly deep, so deep that even if its graphics are only ASCII, your powerful rig WILL slow down.
Luckily for us, there are a plethora of user mods, including a series of graphical additions to the game; even a foreman program to manage your little bearded ones! (By the way, they usually reach 100+ , counting dead ones and newborns; there is guaranteed fun by trying to keep them all feed, drunk, slept, armed and aware from all the external dangers).
I could try to describe more aspects of it, but it would be senseless; this one is a must-see if you dare to call yourself a gamer. Stay away if you don't enjoy thinking time to time; go play any first person shooter around.