1. The Legend of Zelda: Ocarina of Time
There's little new to be said about Ocarina of Time, as it remains one of the most historically important games of all time, as well as one of the best. At a time when other companies were struggling and failing to understand how to transfer 2D gaming concepts and ideas into a 3D world, Ocarina did it so effortlessly that it's hard to believe it was ever a problem.
Set in a world bigger than anyone thought technologically possible at the time, its mythic story spanned cities, dungeons, lakes, mountains, deserts, forest, and divergent timelines. The Z-targeting and combat set the standard for years, and the soundtrack still rings in our ears to this day. Later Zelda games further improved and refined Ocarina's formula, but it was this title that proved such a game could not only exist, but be this extremely good.