For you strategy fans out there, the first DLC named Empire Total War: Elite Units of the West has been released. Unfortunately it's not free, but it adds 14 new units together with some performance tweaks and minor fixes. For example, you can get to play as one of the earliest iterations of the United States Marine Corps:
US Marines (United States) - These are some of the toughest and bravest soldiers the United States can boast. Either on land or at sea this unit is a fighting force above all else. The marines' greatest strength alongside their flexibility and speed in combat is their resolve. They will rarely if ever run from a fight once committed, often preferring to fight to the death than hand an inch of ground to the enemy. Single player campaign requirements: Naval College in any province
You can download the DLC for $3.50 at Steam.
US Marines (United States) - These are some of the toughest and bravest soldiers the United States can boast. Either on land or at sea this unit is a fighting force above all else. The marines' greatest strength alongside their flexibility and speed in combat is their resolve. They will rarely if ever run from a fight once committed, often preferring to fight to the death than hand an inch of ground to the enemy. Single player campaign requirements: Naval College in any province
You can download the DLC for $3.50 at Steam.