Age of Empires II Definitive Edition allows you to choose between the original AI and the HD Edition AI, which is an AI that was added to the original HD edition of the game and the new one which is advanced enough to not require any cheating. The game focuses on building towns, gathering resources and building armies in order to defeat opponents. You have to conquer towns and empires, as you advance one of 13 civilizations through four ages. You can unlock new units, structures and technologies, however, you have to build certain buildings from the current age using the sum of resources.