Gearbox Software releases Half-Life: Opposing Force, an official expansion pack for the original Half-Life, introducing new perspectives and gameplay elements.
Gearbox Software releases Half-Life: Blue Shift, an expansion pack focusing on a security guard’s perspective in the Black Mesa facility.
Counter-Strike, a mod for Half-Life developed by Minh Le and Jess Cliffe, is officially released, becoming one of the most influential multiplayer shooters.
Valve releases Half-Life 2, introducing advanced physics, improved graphics with the Source engine, and continuing the story of Gordon Freeman.
Valve releases Half-Life 2: Episode One, the first episodic sequel continuing the story after Half-Life 2.
Valve releases Half-Life 2: Episode Two, continuing the episodic series and expanding the narrative further.
Valve announces Artifact, a digital collectible card game set in the Dota 2 universe but connected to Valve’s IP reputation including Half-Life’s card design influences.
Valve releases Half-Life: Alyx, a virtual reality (VR) game continuing the Half-Life storyline, revitalizing the franchise after many years.
An experiment in the Xen resonance cascade goes wrong, causing a catastrophic dimensional rift and unleashing alien creatures on the Black Mesa Research Facility.
Gordon Freeman begins work as a theoretical physicist at Black Mesa, setting the stage for future events.
The Combine, an interdimensional empire, invades Earth and rapidly defeats human resistance forces leading to occupation and control of Earth.
Human rebels start organizing to resist the Combine occupation across Earth.
Gordon Freeman arrives in City 17, becoming a symbol and leader of the Resistance against the Combine.
Combine forces systematically crush resistance and maintain control over human population centers, including City 17.
Following the incident, Black Mesa is quarantined and later shut down by government forces.
Resistance successfully infiltrates and controls key Combine installations, weakening their grip on Earth.
The mysterious G-Man appears at key moments, manipulating events, including extracting Gordon Freeman from critical situations.
