If you build up a big area of plains on your board, you can drop your “Farm” piece in the middle, and it converts those plains into richer plains. Put a “Woodcutter” into a bunch of forest, and it harvests that wood and turns it into plains. Set down a “Watchtower,” and it recruits some archer units for every plains tile in its vicinity, and even more for richer fields. You could drop a Woodcutter next to a Farm and Watchtower, and it would turn the forests into plains, the Farm would turn the plains into fields, and the Watchtower would pick up more units for all those rich fields.
That kind of multi-effect combo, resulting from one piece you perfectly placed in the nick of time, is what keeps you coming back to Drop Duchy. The bitter losses come from the other side, like realizing you’ve leaned too heavily into heavy, halberd-wielding units when the enemy has lots of ranged units that are strong against them. Or that feeling, familiar to Tetris vets, that one hasty decision you made 10 rows back has doomed you to the awkward, slanted pile-up you find yourself in now. Except that lines don’t clear in Drop Duchy, and the game’s boss battles specifically punish you for running out of good places to put things.
There’s an upper strategic layer to all the which-square-where action. You choose branching paths on your way to each boss, picking different resources, battles, and trading posts. Every victory has you picking a card for your deck, whether military, production, or, later on, general “technology” gains. You upgrade cards using your gathered resources, try to balance or min-max cards toward certain armies or terrains, and try not to lose any one round by too many soldiers. You have a sort of “overall defense” life meter, and each loss chips away at it. Run out of money to refill it, and that’s the game.