An Immortal Game
Each of the three factions is amazing in its own way and offers you versatile units you can mix-and-match, effectively providing you with multiple tactics to defeat your foes. As Terrans, you can either rush opponents with marines/vultures, build a fleet of 24+ siege tanks escorted by 12+ battlecruisers bombarding everything around you (yeah I did that once!) or launch nukes on the enemy. As Zerg, lay an ambush or overwhelm your enemy with literally hundreds of zerglings! As Protoss, dominate the skies with a fleet of scouts or destroy large groups with psionic storms...the list is endless...the tactics innumerable...the fun, never-ending.
There are complains about the game of course but they are more of an imaginitive nature than game-play criticisms. There is so much possible in a world such as Starcraft that one would feel that Blizzard hasn't utilized its full potential, a fact amply demonstrated by the new units added in the expansion pack. Graphics-wise, the game is understandably dated - but the graphics still look pretty nice - and with animations like nuke, siege tank, cloaking and warping, you really can't complain. Sound is great, specially Terran music and Protoss speech. All in all, Starcraft is a game that will be played for a long while to come and deservedly so. Even if you play it to death, you will still come back to it later and enjoy the experience. Its a legend and I wouldn't be surprised if it is written down in bold letters in a historic timeline.