Unit pathfinding is also supposedly improved upon. When the old and new AIs were pitted against each other in a test, the new one easily defeated the old one.

The original AI had to cheat to be competitive, while the new AI is advanced enough to not require any cheating. Players can choose between the original AI, the updated HD Edition AI that was added alongside the HD Edition of the game, and a newer AI developed for the Definitive Edition. It includes all previous expansions from the original ( The Conquerors) and HD edition ( The Forgotten, The African Kingdoms, Rise of the Rajas). Four new campaigns were added for the new civilizations: Ivaylo, Kotyan Khan, Tamerlane and Pachacuti which is about the Inca civilization and replaces El Dorado from the HD Edition (Lithuanians do not appear as a playable civilization in any campaign however, they represent Poles in the Ivaylo campaign). It features a new expansion called The Last Khans and includes four new civilizations: Bulgarians, Cumans, Lithuanians and Tatars.

The remaster includes new 4K graphics, new improved visuals for troops and buildings, the ability to zoom in and further out and a new spectator mode. The core gameplay elements are shared heavily with the original but Definitive Edition builds upon it. Gameplay of Age of Empires II: Definitive Edition

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