It's always nice to return to a great game in a series, especially when it's the best one.
Age of Empires II is one sequel that is better then the game before it, and it's due to a high amount of additions; civilizations, units, technologies, maps etc and an overall better production value.
The graphics were pretty good when it was released and kept a good framerate, not even dropping when there was over 100 troops on screen. The different art styles lend a bit of variety and even though some of the civilizations share the same style, it feels like it belongs there. The units are detailed quite nicely but they look the same ( not counting civ-only units) and are only different by what color of the side they're on (blue, red, green, etc). The landscape is nice, but feels a tad generic, apart from when the buildings are set on fire, which is a nice addition.
The sound is amazing, from the classical, instrumental music which suits the game quite nicely. The sound effects are your typical affair, which is not to say that it's medicore, quite the opposite. With their screams and their swords clashing, it helps the user fel like they are in control of an army.
The gameplay is spot on, with the excellent control/interface that is used to move and separate units and to send villagers to gather resources. The problem is that the civilizations aren't varied to a certain degree. They have 1 (2 for the Vikings) special unit only they can get and certain bonuses only they can utilize but they pretty much all get the same units and technologies. But not everybody can get every technology in the game. The campaigns provide a great single-player mode and the CPU can put up quite a challenge. The game gets even better in multiplayer but since it's an old game, don't expect much from the multiplayer unless you know some people who own the game. Even with the minor set back for the multiplayer, the single player is still amazing and should be the main reason to buy this game.
For a gamer who doesn't want to spend much money on a game or someone who doesn't have a top-of-the-line computer, this one is a great buy.