Skirmish mode will pit you and a friend (or computer ally) against four computer-controlled enemies, and each AI can take on a variety of different playstyles. Each style is represented by a unique leader, and there are eight of these to choose from.
Also of note is the fact that skirmish mode unlocks all of the game's units regardless of your overall level. If you want to preview some powerful Age of Empires units that are hidden away behind hours of advancement gameplay, skirmish mode is the way to go. Check out the skirmish mode trailer after the break for more details.