Halo: Combat Evolved

Humanity is the midst of a long war against an alien alliance called the Covenant who have been wiping out colony after colony. You hero is Master Chief, who is given no name beyond his rank in the game itself. He is stationed on the Pillar of Autumn, a ship which, per protocol make a jump in a random direction to retreat to avoid revealing the location of Earth. They find themselves at the titular Halo, a planet-sized ring of mysterious origin and function with the Covenant on their heels. Master Chief must repel the Covenant assault and discover the secrets of Halo with the assistance of the female AI Cortana who lives in his suit and gives missions.

Halo: Combat Evolved is a sci-fi first-person shooter with considerable driving elements. Features include friendly NPCs who fight alongside the Chief, squad-based AI where enemies groups work together to flank you under the direction of a leader unit and can be demoralized by his death. They also use cover, set ambushes, etc.