 During the course of a game , players gain XP ( experience ) by completing actions such as constructing buildings , training units , killing enemies and collecting treasures . Whenever a certain amount of experience points are gained , the player can make use of a shipment from their respective Home City . Shipments slow as the game goes on , since more XP is required with every consecutive shipment . This XP is also added directly to the home city and is collected over multiple games , allowing it to level up over time . Players can gear their cards into three different combinations : " Boom " ( economic combinations ) , " Rush " ( military combinations ) , or " Turtle " ( defensive combinations ) . The first few cards chosen are automatically added to the player 's portfolio , where it can be copied onto a deck for use in a game . Later in the game , cards have to be manually chosen because of the limit of cards in one deck . Most cards are available to all civilizations , but some are unique to one . If the Home City being played has more than one deck , the player must select which to use when the first shipment is sent . During a game , players keep this initial deck ; this feature encourages players to build decks that are customized for the map being played on , or that counter other civilizations . The decks support twenty cards . As the Home City improves by level , you may gain an extra card slot for the decks for every 10 levels . 
