** All the main themes. Starting from the [[http://www.youtube.com/watch?v=3MC4YANh_a0 first AoE version]], the [[http://www.youtube.com/watch?v=RRtlWfi6jiM AoE2 rendition]], and finally the [[http://www.youtube.com/watch?v=7ZRAwWZm4h4&fmt=18 AoE3 rendition]]. Each and every single one of these, epic and glorious. And if that wasn't enough, [[https://www.youtube.com/watch?v=omj8Dpl6XNg an orchestra even played it live]]. And it sounds every bit as awesome as the recorded version.
** The [[http://www.youtube.com/watch?v=zyY1M2UY69o Revolution]] theme from ''[[VideoGame/AgeOfEmpiresIII The WarChiefs]]''.
** ''Mythology'' is [[http://www.youtube.com/watch?v=JzDh7a2VEVQ famous for it]].
* ArtificialStupidity: Even on "Hard" difficulty, the AI doesn't present much of a challenge to experienced players, often struggling to construct any sizeable, competitive military force at all. The best custom AI scripts for the second game can single-handedly defeat a team of five default AIs, and it's not unheard of for dedicated human players to take on teams of seven AIs on "Hardest" difficulty (where the AI cheats).
** Ally AIs generally do nothing but gather resources. This is especially irritating in any mission where you are tasked with defending an ally, given that defending yourself from the enemy is difficult enough as it is. Of course, then there are the times when your ally does actually train an army--a nonsensical, ineffective mishmash of units that they send off to their deaths one by one. This is particularly annoying in Online, where NPC armies have a random chance of training an Elite (more powerful) version of a unit instead of the normal unit. Seeing an Elite War Elephant be paraded across the map, being slowly killed by enemy units while not inflicting a single injury on those enemies, is a difficult sight to bear.
--> I need wood! I need wood! I need wood! I need wood! I need wood! I need wood! I need wood!
--> You're being attacked!
--> Ah ha ha ha ha ha ha ha ha ha... HA!
--> Start the game already! Start the game already! (though this one is on purpose)
* OnlyTheCreatorDoesItRight: ''Age of Empires Online'' was frequently accused of this, despite the development team involving a lot of ex-Ensemble staff.
* TearJerker: The sound the elephants make when they die.