Balance
How every unit gets a fair price, how counters work, and the test fights that keep strange armies beatable.

Bears, network play and the Norse shield wall
Day eight: brown bears, moonbears and polar bears join, two computers play a match over the home network, and the Norse get a culture and a shield wall.

War beasts that walk, heroes for every race, and saves
Day seven: war elephants get jointed legs, every race gets heroes, matches can be saved and loaded, and a Steam Deck mystery of white boxes gets solved.

Siege engines with their crews, and arrows that miss
Day four: rams and siege engines with the crews that push them, rats grow to human size, and archers stop winning everything once their arrows can miss.