EE is a rather unique RTS that is somewhat akin to Age of Empires, but stretches upon a much longer period of time. It also features new concepts like buildings (or units) with particular area effects or protections again specific things. The interesting twist of the game is that there's much more to balance between economy and military than there is in for example Age of Empires. However, you should know that this game has two particular 'nuisances': 1. Units, especially ships are navigating terribly and it's sometimes a random back and forth when moving since the one unit wants to go to another place than the other one does. 2. The AI itself is terrible (because the game is more complex than e.g. AoE) and employs an insane amount of cheats to be challenging. This is particularly problematic because the cheats make certain strategies that work against human players moot: For instance, AI enemies get a huge amount of resource income for 'free', i.e. they still get it even if there are no citizens working. That leads to strategic bombardment being not as effective as you'd think it to be, as destroying all town centers will only slightly slow down troop production if such facilities still exist. Overall, this leads to a battle against a AI player making a lot of strategies that would work against non-cheating players not working and alter the gameplay a lot.
