The Legend of Zelda: A Link to the Past

The 1991 SNES entry that established the Zelda formula every game since has followed: light world/dark world duality, dungeon items that unlock new areas, a master sword quest, and exploration that rewards curiosity. The dungeons are perfectly paced, the overworld is dense with secrets, and the Dark World twist halfway through effectively doubles the game. Link Between Worlds proved in 2013 that this template still works perfectly — because the original was that well-designed.