

When a unit's morale is sufficiently depleted, it will be routed and flee the battlefield. Tactical situations such as attacking from a flank or the rear, or depriving a unit of allied reinforcements, also hit morale. Each unit has morale, which increases if the battle goes well, or decrease after heavy casualties, army losses, coming under artillery bombardment, or with the death of the general. Factions can lay siege to settlements, replacing open land battles with street fighting and close-quarter combat. The battlefield terrain and the weather are also important. Players must use 18th-century tactics and formations to defeat their enemies. Each has its own intrinsic advantages, disadvantages, cost, and overall effectiveness. In land engagements, players have an 18th-century army consisting of units such as cavalry, musketeers, riflemen and artillery. Players can now research technologies along a technology tree, advancing in areas such as infrastructure, politics, agriculture and the military. The way armies are produced also differs: in addition to being produced at settlements, generals can now build their armies in the field by recruiting from nearby settlements. The isomorphic religious leaders are Catholic, Orthodox, and Protestant missionaries, Imams, and Brahmin. Isomorphic units also exist for the Ottomans, Persians, and other near eastern nations, replacing rakes with Hashashin, while Indian nations use Thugees for the same purposes, and all nations south and east of the Ottoman Empire use Eastern Scholars instead of gentlemen (although these cannot duel).

Missionaries serve to convert the populace to the state religion, which reduces religious unrest and softens cultural unrest. The former handle research and can challenge other characters to a duel (thus eliminating the diplomatic risk of being implicated in an assassination plot), while rakes perform clandestine tasks such as spying, assassination, and sabotage. The wandering scholars, spies, emissaries and assassins used in previous titles to deal with diplomacy, trade and espionage have been replaced with just three units: gentlemen, rakes, and missionaries. Previous Total War games required the player to promote a governor for each major city, whereas in Empire ministers' qualifications affect the government of all cities, modified in each case by the size of the metropolitan administration, reflecting the shift from premodern city-statehood to modern nation-statehood.

Diplomacy, taxation, and trade have been streamlined to reduce the need for micromanagement, including allowing the player to appoint ministers to govern the nation. The way provinces work has been decentralised: although a central settlement is still used, other locations within a province can generate trade and technology, allowing factions to disrupt a province's productivity without assaulting the main settlement.

It features three main theatres of play: Europe (which also includes North Africa and the Middle East), the Americas, and the Indian subcontinent, as well as four minor trade theatres: the East Indies, the Ivory Coast, the Straits of Madagascar and Brazil. The campaign mode is similar to those in Rome: Total War and Medieval II: Total War, but with several enhancements.
