Yes, I know this is a feature request as old as the game itself, and may well be utterly infeasible without a major overhaul, but I feel compelled to ask again, if only so some game designer in the future might remember: Let us build downward! Let me have a proper basement or cellar, or build a proper dungeon/torture chamber/whatever. I don't need more storage, I don't need you to add more total floors to my house. I just want to be able to trade, say, my third floor for a basement or something.

Thanks for reading my utterly insane request that will never happen. 🙂