Half-Life 2 is a 2004 first-person shooter (FPS) game developed and published by Valve Corporation. It was published for Windows on Valve's digital distribution service, Steam. Like the original Half-Life (1998), Half-Life 2 combines shooting, puzzles and storytelling, and adds features such as vehicles and physics-based gameplay. The player controls Gordon Freeman, who joins a resistance to liberate Earth from the alien Combine empire.

Half-Life 2 was created using Valve's Source game engine, which was developed simultaneously. Development lasted five years and cost US$40 million. Valve's president, Gabe Newell, set his team the goal of redefining the FPS genre. They integrated Havok, which simulates real-world physics, to reinforce the sense of presence and create new gameplay. They also developed the characterization, with more detailed character models and animations.

Valve announced Half-Life 2 at E3 2003 with a release date of September of that year. They failed to meet the release date, leading to fan backlash. A year before its release, an unfinished version was stolen by a hacker and published online, which damaged the team’s morale and slowed their work.

Half-Life 2 was released on Steam on November 16, 2004. It won 39 Game of the Year awards and has been cited as one of the best games ever made. It was ported to Xbox, Xbox 360, PlayStation 3, macOS and Linux. By 2011, it had sold 12 million copies. Half-Life 2 was followed by the free extra level Lost Coast (2005) and the episodic sequels Episode One (2006) and Episode Two (2007). In 2020, after canceling Episode Three and several further Half-Life projects, Valve released a prequel, Half-Life: Alyx.

Gameplay

This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources in this section. Unsourced material may be challenged and removed. (January 2024) (Learn how and when to remove this template message)

A screenshot of the player engaging a group of antlions with a pulse rifle. Along the bottom of the screen, the player's health, suit charge level, and their ammunition is displayed.
Like the original Half-Life (1998), Half-Life 2 is a single-player first-person shooter (FPS) in which players control Gordon Freeman. It has similar mechanics to Half-Life, including health-and-weapon systems (though with fewer overall weapons) and periodic physics puzzles, except with the newer Source engine and improved graphics. The player starts without items and widens their arsenal over the course of the game. While the game is mainly linear, effort was put into making exploration rewarding and interesting; many optional areas can be missed or avoided.[1]

A diverse set of enemies is present, which usually require being approached with different tactics: some coordinate in groups to out-maneuver or out-position the player; others, such as the Manhack, fly directly at the player through small openings and tight corridors.[2] Others use predictable but powerful attacks, while others hide before swiftly attacking the player. Gordon can kill most enemies with his weapons, or make use of indirect means, exploiting environmental hazards such as explosive pressurized canisters, gas fires or improvised traps. In chapters ten and eleven, Gordon can be joined by up to four armed Resistance soldiers or medics and can send his team further from him or call them back.

Many of the features use the Source engine's detailed physics simulation. Two sections of the game involve driving vehicles. Instead of button-oriented puzzles from Half-Life, environmental puzzles are also introduced with makeshift mechanical systems, revolving around the player's new ability to pick up, move, and place objects. Solutions involve objects' physical properties, such as shape, weight, and buoyancy. For example; In chapter three, "Route Kanal", the player is required to stack cinder blocks on a makeshift see-saw ramp to proceed over a wall. Alternatively, the player can build a crude staircase with the blocks, so the puzzle may be solved in multiple ways.

Part-way through the game, Gordon acquires the Gravity Gun, which allows him to draw distant objects towards himself or forcefully push them away, as well as the ability to manipulate larger and heavier objects which he otherwise cannot control. These abilities are required to solve puzzles later in the game. They can also be used in combat, to throw heavy objects at enemies or to shield themselves from gunfire.

The game never separates the player with pre-rendered cutscenes or events; the story proceeds via exposition from other characters and in-world events, and the player can control Gordon for the entirety of the game. Most of the backstory to the game is simply alluded to or told through the environment. Even tutorials are mostly placed in the environment or in dialogue. The few pop-ups that appear inform the player only of keyboard bindings for actions.

Plot
After the alien invasion at the Black Mesa Research Facility, a multidimensional alien empire known as the Combine invaded and subjugated Earth. Approximately twenty years after being placed in stasis, Gordon Freeman, the player character, is awoken by the G-Man (Michael Shapiro), who cryptically informs Gordon that "his time has come again" before celestially inserting him into a moving passenger train bound for City 17, an Eastern European city which houses the Citadel, a several-miles-tall tower which serves as the headquarters of the Combine on Earth. Helped by undercover Resistance member Barney Calhoun (Shapiro), Gordon attempts to reach the laboratory of Dr. Isaac Kleiner (Harry S. Robins) before being beaten and arrested by Combine officers. He is rescued by Alyx Vance (Merle Dandridge), who takes him to Dr. Kleiner's lab. During Dr. Kleiner’s attempt to teleport Gordon to the main Resistance base at Black Mesa East, Gordon is accidentally, briefly teleported to the Citadel office of Dr. Wallace Breen (Robert Culp), the Combine’s puppet ruler of Earth, alerting Dr. Breen to Gordon’s presence. Gordon is subsequently forced to progress to the base using the city's canal system, navigating it on an airboat.

Upon his arrival at Black Mesa East, Gordon reunites with Eli Vance (Robert Guillaume) and meets Dr. Judith Mossman (Michelle Forbes). Alyx introduces Gordon to her pet robot Dog and gives Gordon a Gravity Gun. Black Mesa East is suddenly attacked by Combine forces, who capture Eli and Judith; Gordon is forced to escape through the zombie-infested ghost town of Ravenholm, aided by its lone inhabitant, Father Grigori (Jim French). Escaping the town, Gordon reaches a Resistance outpost, whose inhabitants provide him with a dune buggy. He drives across Highway 17 to reach the Combine prison of Nova Prospekt, where Eli and Judith are being held. He breaks into the prison and reunites with Alyx. They locate Eli and discover that Judith is a Combine spy. Before they can stop her, Judith teleports herself and Eli to the Citadel. The teleporter explodes moments after Gordon and Alyx use it to escape Nova Prospekt.

Returning to Dr. Kleiner's lab, Gordon and Alyx learn that the teleporter malfunctioned and that a week has passed, during which time the Resistance has launched a full-scale armed rebellion against the Combine. Aided by Barney and Dog, Gordon fights his way inside the Citadel. He makes some progress in climbing the tower before he is captured and taken in a transport pod to Dr. Breen’s private office, near the tower’s apex, where he and Judith are waiting with Eli and Alyx as captives. Dr. Breen reveals that he intends to use his captives as leverage during negotiations with the Combine, which contradicts what he had previously told Judith.[3] Angered, Judith frees the three captives before Dr. Breen can teleport them off-world. Dr. Breen attempts to escape using a teleporter on the Citadel’s ro