Age of Empires Online takes the classic Age of Empires real-time strategy gameplay, and places it into a quest-based online structure. Similar to the previous games in the series, most missions ask you to build up an economy, then an army, then crush all those who oppose you, with occasional more unusual missions. The differences come between missions; your capital city allows you to equip your soldiers, unlock technologies, craft items, and so on. Items, either found in missions, bought, or crafted, give per-unit-type benefits. For example, a copper sword might give a 3% damage bonus to Hoplites. Technologies are unlocked using technology points, which are acquired through gaining levels. Only unlocked technologies can be researched in a mission. Both story missions and side missions are available, with some missions repeatable to gain more XP, items, and gold.
At the time of release, Greek and Egyptian civilizations are available, with more civilizations promised. Each civilization has unique art, units, and storylines. Age of Empires Online is a free-to-play game, but each civilization can be upgraded by paying real money. The upgrade will unlock high-end items, units, and abilities. Other upgrades include quest packs and cosmetic items.