I am currently playing above an aquifer. I embarked near a necro tower and with the level of immigration I'm getting I can't divert any resources from building the fort for accommodating the peasants into piercing the at least two level aquifer. It does feel very medieval, given that I don't have the resources to properly accommodate everyone so everyone gets tiny huts if anything, and when the siege comes everyone who values life crams themselves into the single secure building in the shambles of a village, the keep, and hopes the food doesn't run out. I have three forges, four smelters and six wood furnaces running constantly to smelt the copper I brought on embark and have been buying up by the ton from the caravans. Copper, by the way, is the highest quality weapons grade material available to me until I manage to be siege free through summer for the humie caravan - my civ doesn't even have tin for bronze, and I have decided for Fun that buying steel from your civ is exploity when your civ has no iron. Most fun fort of mine in ages.
My no nos:
-don't buy steel from your civ if they have no iron (anvils are fine, reistically a copper or stone anvil works just fine, pretend the steel anvils are actually gabbro)
-don't use danger rooms
-don't spam traps, particularly cage traps. A few to capture wildlife or the occasional prisoner of war are fine.
-don't rely on subterranean farms or any egg layers or non grazers for food. It's too easy for even a vague sense of realism.
-don't use cheap super traps like an atom smasher corridor. It's boring. Atom smahing garbage is cool.
-do embark on an aquifer near an aggressive necro tower with only an anvil and 200 urists of malachite.