Imperia Online is set in a Medieval world. The game’s version 6, called ‘The Great People’, is the current one even though there still are tens of active version 5 realms. Each player starts the game as the emperor of an undeveloped Province. The Province can be developed by constructing – and later upgrading – various economic and military buildings amongst which resource-generating buildings as well as universities, used for researching key technologies. Recruiting and training military units allows players to attack other Provinces to plunder their resources, and defend from enemy attacks. Players may trade their resources with other players after they’ve built a marketplace on their own territory. The Province grows into an empire through territory annexing and colonizing. Players can communicate with each other using in-game messages, and may join alliances for military and economic co-operation with other players.
Resources are needed for developing Provinces and training units. Three of them – Wood, Iron and Stone – are produced by resource-generating buildings: Lumber mill, Iron mine and Stone quarry. The resource output can be increased by upgrading the three generating structures so that new work vacancies are created. The fourth main resource is Gold. It is used for almost any type of research, military training and building development. It is also the universal currency for buying and selling all three other types of resources. Gold is gathered through taxes, selling resources on the Marketplace, fortress sieges, deposit interests, and as one of the possible rewards from the various caskets awarded in the game. There are also the so-called ‘Special resources’ that can be found throughout the realm. There are more than 50 types of special resources and their main purpose is granting bonuses to various in-game statistics like resource production, military units, experience gain, etc.
There are 29 structures that can be built and upgraded in the capital. Buildings are constructed and upgraded through a main building, called ‘Town hall’. The Town hall is the building every player starts the game with. The two main types of buildings are separated in tabs ‘Economy’ and ‘Military’. Each building has a special function. For example, the two universities that make possible the development of Military and Economic technologies.
Imperia Online’s battle system is rich and complex, despite being built with 4 main types of military units only. The 4 main categories of units are Light, Heavy, Elite and Siege Engines. The battle system requires skill and tactical thinking from the player since there are multiple army formations that can define the end result of the battle. There are three types of attacks: Field Battle, Fortress Siege and Pillage. The first one sends the troops to fight only with the opponent’s field army, without sieging the Fortress or pillaging the civil population. The only profit for the attacker are military points for slashing enemy units and honor points. Fortress siege is conducted after a successful Field battle for the attacker. A successful Fortress siege loots resources. If the player chooses Pillage, their troops engage the opponent’s civil population. Gold is earned for every killed villager. It’s punished with Honor drop.