Dwarftown was meant as a tech demo/experiment in dungeon generation. Not much from the original project remained (in a way, the game can be described as “Madness minus madness”), but I still have a playable, hopefully interesting little game.
What I had most fun with was the lighting/FOV system. Creating a lighting engine for a roguelike is non-trivial when you have consider things like updating the map after opening a door, or a wall that is lit from one side but dark from another. I don’t know if the final result is intuitive, but it makes the dungeon look prettier and allows for some fun hiding in the shadows.
I also got to play with various map generation methods – used algorithms are: cellular automata, recursive tree-like corridor carving, and simple “throw rooms into the map at random”, combined with libtcod‘s pathfinding to ensure connectedness.