Concentrating on the late medieval period, Age of Chivalry: Hegemony replaces or significantly alters each of the civilizations in the original game, while adding a number of new ones, allowing the player to control Central and Western European states. Many new units and technologies have been added and gameplay dynamics have been changed considerably in this complete overhaul of Age of Empires II.
Its great. Makes the game feel fresh and more difficult, the AI is brutal but you'll adapt, it makes AOE2 base seem easy by comparison, be warned with under patch and several friends it can lag, but that's my own fault for maxing out user patch's pop limit lol