: Dedicated, deep-branching focus trees for Hungary, Romania, Czechoslovakia, and Yugoslavia . These allow players to navigate historical tensions or pursue alternate histories, such as reviving the Austro-Hungarian Empire as Hungary.
The free 1.4 update, which accompanied the DLC, brought several major base-game overhauls: Hearts of Iron IV Death or Dishonor v1.4.2
: A new mechanic allowing nations to license military technology from more advanced powers or sell their own designs for a profit. : Players can upgrade or repurpose older military
: Players can upgrade or repurpose older military equipment (e.g., converting captured tanks into tank destroyers) rather than simply retiring them. Changes in Version 1
: New impassable terrain, such as the Sahara Desert, changed how warfare is conducted in North Africa.
: New levels of puppetry and autonomy specifically for fascist regimes. Changes in Version 1.4 "Oak"
: A complete redesign of the air combat interface, mission selection, and wing management on the map.