The Atlanteans are a civilization with a heavy emphasis on quality over quantity. As a result, their units are powerful but expensive and often take up multiple population slots.
The Atlanteans have a powerful economy due to their villager unit, the Citizen. Citizens are expensive but are very efficient. They can build faster than the villagers of other civilizations and do not need to drop off resources, instead sending them directly to the stockpile. This saves time as they do not need to move between points and resources as they do not need to build a drop off point. As a result, the Atlantean economy develops fairly quickly. In addition they have the ability to build Town Centers in the Archaic Age, allowing them to expand right away. Their military is composed mainly of infantry. The Murmillo is the standard unit for the Atlanteans and is available in the Classical Age. They cannot train any other units from their barracks during this time. Instead other Classical Age units are trained from the Counter-Barracks, which trains units made to counter specific units. In the Heroic Age cavalry and archers become available. Another major strength for the Atlanteans is that they can use their God Powers multiple times. This allows the Atlanteans to harass the enemy with God Powers or strengthen themselves to provide an advantage. Atlantean Heroes are fairly easy to mass. Instead of having a specific hero unit they can upgrade any of their units to heroes, which grants them an attack bonus against Myth Units in addition to whatever strengths they already possessed. This allows Heroes to participate in general combat, not just against Myth Units.
Citizens, while useful, are very expensive and take up multiple population slots. This makes starting off somewhat more difficult as training them requires more time and resources, although this is compensated to a degree with the extra starting resources Atlanteans get. Population is often an issue because of the Citizen. In addition upgrading units to Heroes increases their population space. As a result, the Atlanteans cannot train as many units as other civilizations, which is the very reason they focus on having a few strong units as opposed to a large army, offsetting the problem to an extent. The Atlanteans also lack any long range siege unit, forcing them to get close to enemy defenses, which leaves them vulnerable to a quick counter-attack by an attentive enemy. The Fire Siphon is also impractical in that it costs 5 in population and can only be created in the Mythic Age.
Atlanteans can be considered as a booming civilization that has great economy and high quality military units; all of the three major gods are in one way or another able to give their followers a large economic boom. Atlanteans at the late game can become nearly unstoppable, so their opponents must focus on attacking their villagers to disrupt their economy.