Part 9/11:
The arrival of Gordon Freeman, the series' protagonist, catalyzed their efforts, uniting various factions against the Combine. His actions incited a massive uprising culminating in the collapse of City 17's Citadel, a pivotal moment that severed the Combine's hold on Earth.
The Combine's Remaining Threat
While their reign was momentarily disrupted, the fate of the Combine is far from settled, as their ambitions continue deeper within the multiverse. The final sequences hint at their far-reaching grasp and extensive empire, evidenced by the reveal of Dyson Spheres and other advanced constructs meant for enhanced control and resource extraction.