Metal Gear Solid 3: Snake Eater

Set in 1964, this is the origin of the spy saga, a prequel that sends an agent code-named Snake into a Soviet jungle to extract a scientist and, soon after, to hunt down his former teacher, the woman who trained him and has apparently defected. You stalk through wilderness with no map markers, hiding in grass, eating what you catch, and patching your own wounds. It is a stealth game that turns survival into the core loop, and it builds toward a final confrontation between mentor and student that recasts everything the series later becomes. Strange, sincere, and built around one of gaming's best villains.