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"Therefore I say, yes, I am a collaborator. We must all collaborate, willingly, eagerly, if we expect to reap the benefits of unification. And reap we shall."
Wallace Breen[src]

The Combine, abbreviated as CMB, and referred to in propaganda as "Our Benefactors" by Wallace Breen,[2] is an immense inter-dimensional empire, comprised of a number of species either as allies or as slaves. The Combine's ultimate goal is to enslave and control the Multiverse.[3]

Following the Black Mesa Incident, and the death of the Nihilanth, the Combine invaded Earth and emerged victorious from the ensuing war against the humans in a mere seven hours with their extremely superior technology and the assistance of numerous enslaved species, completely taking over all of human civilization and ruling with an iron fist, oppressing and murdering humans while destroying the planet slowly via drainage of resource. Nevertheless, humanity did not remain subjugated, and nearly twenty years later, Earth's Resistance culminated in The Uprising, and the Combine were beaten thrice in pivotal battles.

These events were spearheaded by Gordon Freeman, having been released by The G-Man from stasis. The Combine serves as the overarching antagonistic force of the overall Half-Life series and is the main antagonistic force of Half-Life 2, its episodes, and Half-Life: Alyx.



A Combine Advisor.

The Combine is a massive empire spanning countless parallel universes and dimensions, and includes an unknown number of sentient species. The Combine's ultimate goal is to conquer and harness entire universes and dimensions.

Details of the Combine's leadership and administrative structure remain unknown, as do whether they consist of an economy, or even a society that exists beyond the limits of human understanding. On Earth, beings called the Advisors are responsible for overseeing all communication and interaction between the Combine and the Earthly occupation, as well as ruling all Combine forces on earth through Dr. Wallace Breen, who serves as humanity's Administrator and representative on Earth.

The Combine is composed of an untold number of species, with entire alien ecosystems enslaved to their will. They seem to only assimilate intelligent species from the universes they conquer, and manipulate these species through many means, including bioengineering and artificial implantation. The products of the Combine's re-engineering process are known as "synths" — synthetic robots that serve a variety of functions within the empire.

On Earth, the Combine notably uses their technology to create armies of super-soldiers, resulting in a highly mobile and adaptive military force that can respond to any threat and crush any opposition.

The Combine Overwatch on Earth is a notable example of this: Overwatch Soldiers, humans surgically modified with Combine technology, are overall much deadlier and more resilient than normal human beings. They are also highly trained, and can adapt well beyond the confines of Earth, in other universes and dimensions if needed, as in-game dialogue mentions potential deployment of Overwatch units across the Combine Empire in a "permanent off-world assignment." Assignment on other worlds is considered a terrible fate for Overwatch soldiers unfortunate enough to be stuck with it, and is often used as a punishment or threat only. Equally dire is the threat of "permanent off-world relocation" directed towards citizens. Judging by dialogue from Breen, many of the territories under control by the Combine are nigh-uninhabitable by humans without life support systems.[4]

Vocal stress is on the first syllable. The name is pronounced COM-bine, as in Combine harvester, opposed to the verb form com-BINE, as in "to join together or unite." Dr. Breen refers to the Combine Soldiers and Civil Protection as "The Transhuman Arm of the Combine Overwatch" [2] in Nova Prospekt, verifying that "Combine" is an accepted name of the empire, even by the Combine itself.

It is unknown how many worlds the Combine has under its control. Being an inter-dimensional empire, they may have hundreds, if not thousands, of universes under their control. It is known that the Combine invaded the homeworld of the Nihilanth's species and inflicted a total genocide against them, with only the Nihilanth able to escape the onslaught by seeking refuge in Xen.[5] It brought with it members of several species, both its allies and its slaves, including the Vortigaunts.[5][6]

Following the Black Mesa Incident and subsequent Seven Hour War, Earth became the Combine's most recent (known) annexation. Following standard Combine procedure, Earth's dominant species were modified to form a new arm of the Combine military, and the planet's resources were systematically stripped.

Combine teleportation

The Combine Empire is incredibly advanced technologically, being able to teleport to an entirely different plane of reality. Through this technology, the Combine can traverse entire universes and dimensions in their conquests.

However, the Combine appears to have a limited grasp of local teleportation. Dr. Mossman explains that while the Combine can teleport from one universe to another, they do not know how to teleport between different locations in the same universe, and are instead reliant on far less powerful means of local transportation.

The teleportation method developed by Black Mesa, on the other hand, enables intra-universal (local) translocation. As a result, the Combine aims to obtain as much information on their teleportation technology as possible. Under the tutelage of Eli Vance, Dr. Mossman helped the Combine build a comparatively rudimentary teleporter with such capabilities in Nova Prospekt, but it was destroyed during Alyx Vance and Gordon Freeman's escape.

The Combine's teleportation is also far more resource-intensive than Black Mesa's teleportation. Since the Combine is teleporting in-between universes, a large amount of power and gargantuan pieces of machinery are required to perform teleportation, as seen at the end of Half-Life 2, where Dr. Breen attempts to escape from the Citadel using a Combine teleporter. This teleporter requires a dark fusion reactor to power it.

Little is offered in the way of explanation for teleportation physics, but it's known that the Resistance's teleporters use Xen as a "dimensional slingshot" — whereby instead of entering and exiting Xen as Black Mesa originally did, teleports could instead "swing around" the borderworld and return to their own dimension without the need to use Xen as a layover. Combine teleporters cannot do this, instead apparently using "string-based" technology, similar to Black Mesa's "Calabi-Yau model." However, according to Mossman, the Combine fail at this method because they don't "factor in the Dark Energy equations".

Combine on Earth

Invasion of Earth and the Seven Hour War

Newspaper clippings found in Eli Vance's lab in Black Mesa East depict scenes from the Portal Storm and the following Seven Hour War. Note the sections stressed by a yellow highlighter pen.

In the wake of the Nihilanth's demise, the breach between Earth and Xen became unstable and created a series of immense portal storms, creating several interdimensional gateways all over the planet. Seizing the opportunity, the Combine used these portals to launch a massive invasion of Earth. As massive Combine armies and other extraterrestrial creatures, such as the Xen aliens, flooded the planet, a conflict known as the Seven Hour War ensued, which was a brief but consequential conflict between the Combine armies and the militaries of Earth. Due to the technological superiority of the Combine military and the sheer numbers of Combine troops, it only took seven hours for all of Earth's militaries to be completely and utterly defeated, and billions of human casualties and deaths having been afflicted. The former administrator of the Black Mesa Research Facility, Dr. Wallace Breen, discovered how to communicate with the Combine and was tasked by the United Nations to negotiate a surrender on Earth's behalf by any means necessary. The resulting terms had Earth fall completely under Combine occupation, with Breen appointed Earth's administrator.[7]

Suppression Field

A symbolically empty playground in City 17.

Main article: Suppression Field

The Combine imposed a "suppression field," inhibiting human reproduction. The field prevents the formation of certain protein chains vital to human embryonic development; thus, the global human birth rate has reduced to zero, and has ensured that the humans currently alive will be the last generation.

Doctor Breen addresses this issue to the people via a broadcast during the early levels of Half-Life 2 as the response to a letter written to him by a "concerned citizen." Avoiding answering the question itself, Breen explains that he believes the field is a positive influence. Breen claims it supposedly nullifies one of mankind's basest, most instinctual urges claiming the field deactivation will happen once the humans prove that they "no longer need it."

During Half-Life 2, Resistance members occasionally make humorous remarks about the suppression field, such as "When this is all over, I'm gonna mate." Initially, it was thought that the suppression field somehow prevented human sexual urges, mainly due to Dr. Breen's statement that it suppressed "the urge to reproduce." This statement may be referred to as the suppression field's physiological effects causing human "urges" to diminish rather than to stop outright.

In Half-Life 2: Episode One, it is revealed by Dr. Isaac Kleiner during his transmissions throughout the city that the suppression field has become paralyzed with the Citadel's near-destruction. He says that everyone who has escaped City 17 "should do their part" in the repopulation of the human species "before the Combine attempt to restore their dominion." When Alyx Vance hears this, she remarks, "Is Dr. Kleiner really telling everyone to... get busy?" Eli Vance jokingly gives Alyx and Gordon a similar suggestion, claiming to want grandchildren.

There are no children present in Half-Life 2 and its episodes because of the Combine Suppression Field by the Combine. Given that the Combine has been occupying Earth for nearly twenty years, the humans Gordon Freeman sees throughout the game are possibly the last humans born naturally.

Evidence such as the ghostly laughs and screams of children heard in the playground outside one of the apartments in the first chapter of Half-Life 2 a crying couple showed shortly after. The player does not see any children in the most human-populated areas, remarks by Resistance members such as "I'm glad there are no kids around to see this." The presence of discarded toys such as baby dolls during the game seem to be past reminders.

According to Half-Life 2: Raising the Bar, children were present in the early stages of the game development in City 17, called the Combine Factories. Adults and children were to work in this area closely watched by Metrocops and Combots. In the Cremator Factory, children were supposed to build enemies called Cremators. As the concept of human reproduction disabled by the Suppression Field evolved, children finally got cut with the whole area, along with the Cremator.

Mind control and memory replacement

Main article: Memory Replacement

A Combine soldier connected to a memory replacement device.

Comments at a train station at Half-Life 2's start suggest the Combine has been drugging the populace through their water supply. One of the citizens' remarks, "Don't drink the water... they put something in it, to make you forget. I don't even remember how I got here." This drugging is never mentioned again after this. Plus, this citizen sounds a bit crazed. This drugging may be reinforced by the numerous soda machines stocked with "Dr. Breen's Private Reserve," which freely dispenses water in a standard 12-ounce can.

The insinuated reason for this supposed mind control is humans forget why they hate the Combine. This mind control makes the Humans accede to the Combine's (and Breen's) demands. This mind control creates a fresh mental template for forced re-education.

it's also likely that it quite simply gives the citizens of earth amnesia, to keep them disorientated. This would make sense, as they moved around constantly to avoid making friends or new family and to keep them uncomfortable and constantly having to adjust to new surroundings and drugging them so they can't even remember how they got there would assist in that goal of attempting to prevent organized revolution.

A Combine radio transmission to Civil Protection officers states: "Reminder, memory replacement is the first step to rank privileges." This statement could explain why none of the CPs can join the Resistance after the Uprising (apart from Barney Calhoun, a double agent for the Resistance to begin with.) Their memories may either forbid them from harboring any negative thoughts toward their Combine overlords or program them to believe in protecting the Combine.

However, Barney suggests the opposite when, during Episode One, he states that "now it looks like we're gonna have to cut a path through every chicken-shit Metrocop who's having second thoughts about defending City 17!"[8] although this may simply be a derisive attempt at humor in light of their circumstances.

Indications that the Combine are capable of, and regularly perform, forced memory replacement are present in the game's data files—specifically, the model (above) named "soldier bed," seen later inside the Citadel during Episode One. This model closely resembles that of concept art in Half-Life 2: Raising the Bar. The machine itself consists of Combine emitters and equipment; attached is an arm-like device holding a human body. Lastly, a shell-like apparatus containing three different screens and panels envelops the head. Accompanying this model is a small group of sounds resembling harsh subliminal messaging; this audiovisual messaging system explains the military training used by normal post-human individuals.

This model, in addition to several bizarre sounds of voices in the data files, suggest that this "brainwashing" memory replacement is an important part of Transhuman orientation. The process of instilling Combine propaganda, erasing and, eventually, replacing memories results in a soldier incapable of rebelling against Combine influence, as well as enabling Transhumans with no military background to become part of the highly specialized Overwatch forces.

Human genocide

Graffiti sprayed near Black Mesa East and other places (such as Matt's home), with a Combine (or possibly Resistance, or even a recycled Conscript) soldier holding a baby next to the word 'Caste'.


The Combine does not flinch at committing acts of extreme brutality and even genocide to maintain control over the human populace. In the Half-Life 2 Chapter Route Kanal, a refugee base is raided, and a few members of the post are lined up against the wall and shot just as Gordon arrives. The town of Ravenholm was extensively shelled resulting in the zombification of (nearly) all its residents. Throughout the Highway 17 chapter, the player encounters numerous bodies in the coast houses. Some bodies in these houses have been burnt in bonfires by the Combine.

Depletion of Earth's resources

The draining of Earth's oceans is easily the most striking sign of the Combine's rule on the planet.

It is evident at several points in the game that the Combine is depleting Earth's natural resources.

One of the official Half-Life 2 descriptions details how Gordon Freeman must return to "an Earth infested with aliens and being picked to the bone."[9]

One of the most noticeable signs is that Earth's ocean levels have dropped dramatically is during the coastal chapters Highway 17 and Sandtraps and the waterways of City 17 in Route Kanal and Water Hazard. The coastline is littered with boats and ships resting on what was once seabed, and various docks and piers are no longer standing in water, but are instead towering over the now traversable landscape.

At Highway 17's beginning, Gordon arrives at a harbor a distance from the water's edge. Indications of the previous sea level judged by moss gathered on harbor structures (although the moss levels are somewhat inconsistent) places the former sea level several feet higher than what is now the ground.

The book Half-Life 2: Raising the Bar mentioned that this massive, planet-wide water drainage is accomplished through the presence of a giant Combine "drain," actually a teleporter, which sends the water to other Combine-enslaved planets.

More generally, parts of the game world are flooded with parasitic Headcrabs and toxic waste, making them inhospitable to human life. Infrastructure is either decaying (as with Highway 17, which is in a state of incredible disrepair and littered with old rusting cars), or rendered useless (as with Nova Prospekt, where the traditional prison area is mostly flooded and run down).

Animals are rarely seen inside and outside of City 17, suggesting that they are critically endangered; although strangely, birds are seen regularly throughout Half-Life 2. The Fisherman in Lost Coast comments that there is no fish left to eat, only leeches that devour anyone who steps into the ocean, posing a further threat to humanity. Agriculture seems to also have been greatly diminished, as Russell's comments during Half-Life: Alyx indicate most species of livestock have been driven extinct.

Additionally, City 17 itself is becoming devoured, as Combine Walls spread outward from the Citadel, consuming the city's buildings. It is unknown whether the Combine is purely using this method to destroy the city, or whether the Combine is gathering raw materials from the city's structures.

During the development of Half-Life 2, the Combine originally had an industrial facility called the Air Exchange, which gradually absorbed Earth's air and replaced it with chemicals and other murky gases. These gases were harmful to humans but most likely ideal for an environment that the Combine master race could inhabit. It was up to Gordon Freeman to travel to the Combine Air Exchange after the prison levels. Gordon's actions at the Air Exchange were to trigger the human insurrection against the Combine in City 17 but dropped and made to happen due to Gordon's actions at Nova Prospekt.[1]


"Dove" poster commonly seen through City 17.


The Combine heavily relies on propaganda to assure their influence on Earth and remind its residents of their presence. Combine units - humanoid and Synth - bear insignias, logos, and other Combine markings. Many Combine posters are around City 17 and its sector (including the Coast, Nova Prospekt, etc.). Most of the time poster includes two common Combine symbols, with variants in color and image backgrounds. Most Combine imagery is quite abstract, and the intended messages can be very subtle.


Main article: Breencast

Breencasts are regular broadcasts made by Earth administrator Dr. Wallace Breen, delivered to the populace of Combine-controlled towns and cities via private televisions and, more commonly, large video monitors mounted on walls in public places such as town squares and railway stations. In his speech on human instinct, he refers to the Combine as "Our Benefactors" and describes their empire as a "universal union". As the messages loop, all announcements could be pre-recorded. A few citizens in the first chapter say the messages are pre-recorded.

Combine military technology

The Combine uses the technological resources of other civilizations against them. Weapons, vehicles, and other technology are assimilated into the Combine armory; to this end the Overwatch utilizes Earth's small arms, armored personnel carriers, trains, and helicopters, often re-designing them for greater efficiency. This appears to have been a gradual process, as Combine units in Half-Life: Alyx appear to have assimilated most Earthly vehicles, but almost exclusively use original, non-Earthly weaponry such as the Pulse SMG or Heavy Shotgun.

Most of Combine's military units on Earth are Human, augmented like Overwatch Soldiers or otherwise. Other vehicles and machines used by the Combine are clearly of non-human origin; examples of this are the Strider and the Gunship, both derived from living creatures that are possibly Transbeings of other enslaved civilizations.

Nova Prospekt proper, while a Combine stronghold, has very little evidence of occupation. The building itself and its coastal defenses seem to be recycled human structures hastily cobbled together. Indeed, most areas actually constructed by the Combine feature little unique architecture.

Combine Soldier fighting Antlions along the Coast.

Combine Overwatch

Main article: Overwatch

The primary military force of the Combine on Earth is the Combine Overwatch (referred to by Dr. Breen as the "Transhuman arm of the Combine Overwatch.")[2] composed of human beings modified into "Transhumans" (or "post-human," as referred to by Dr. Kleiner) cyborgs. They are the most frequently encountered foes throughout Half-Life 2.

Although seemingly used primarily on Earth, for obvious reasons, several Overwatch messages indicate the Combine deploys its Transhuman soldiers to other Combine territories throughout its empire, sometimes as punishment. These modified humans have proven to be efficient killing machines against any foe that stands in their way.

It is important to note that Civil Protection units are not hybrids, and are human.

  • Civil Protection: The quasi-"thought police" that patrols the cities, monitor the public airways, and conduct randomized raids. Considering Civil Protection evidently receive little to no biomechanical augmentation, some Resistance members, such as Barney Calhoun, join Civil Protection to work as undercover operatives to gain insight on the Combine's innerworkings and operations.
  • Overwatch Soldier: The military force of the Combine's occupation of Earth. Overwatch Soldiers patrol and enforce Combine law outside of city boundaries. They include the Shotgun Soldier and the Nova Prospekt Prison Guard.
  • Overwatch Elite: The Elite soldiers of the Combine Overwatch. They have undergone extensive augmentations and are seen either guarding the Citadel or leading squads of regular soldiers.
  • Stalker: Mutilated, drone-like slaves created from dissident Citizens and captured Rebels.

Overwatch Commandos

Half-Life: Alyx introduces the Commando units, a special force group separated from the main military branch that seems to be used to deal with particular and hazardous situations involving a dangerous environment and unconventional enemies :

  • Combine Grunt: The lowest rank in the Commandos hierarchy, Grunts are the most commonly encountered Combine military unit in the game, apparently tasked with all matters not directly correlated with military confrontation. Grunts are often tasked with less-than-desirable, menial tasks above the paygrade of Civil Protection.
  • Combine Ordinal: Ordinals act as commanders of Grunt squadrons and can be seen leading them throughout the Quarantine Zone. Though encountered together less often, other units appear to take orders from Ordinals as well, indicating they occupy a high station in the overall chain of command.
  • Combine Charger: Well-armored units, Chargers specialize in direct confrontation of targets. Uniquely, they are equipped with a heavy shield to block oncoming attacks, and are capable of using this shield to temporarily blind their target.
  • Combine Suppressor: Heavy units with equally heavy weaponry, Suppressors are incredibly formidable tank units who specialize in pinning its targets down with heavy fire, even from great distances, allowing lighter units to advance with little resistance.

Combine Synth

Main article: Synth

Synths are creatures that, through imposed evolution and alteration by the Combine, have been transformed into biomechanical weapons. Synths have come to fit a particular niche in the Combine military. Once self-replicating organic creatures that originated from different worlds, they were enslaved and assimilated into the Combine to become the military's backbone.

Various types of Synth have been brought over to Earth by the Combine. Synths were likely the primary forces used by the Combine during the Seven Hour War. The human-derived Combine units, and technology such as hunter-choppers and APCs, would have only been developed after the Combine's rule on Earth had been established.

  • Advisor Pod: The escape pods used by the Combine Advisors.
  • Crab Synth: Never actually fought, but seen in Half-Life 2 in the Citadel. Encountered in the Half-Life 2 Beta.
  • Dropship: Primary troop and weapon transport of the Combine.
  • Gunship: Assault aircraft that usually attack in groups of two for protection.
  • Hunter: Medium ground assault units, similar to Striders but still quite different.
  • Mortar Synth: Never actually fought, but seen in Half-Life 2 in the Citadel. Also encountered the Half-Life 2 Beta.
  • Shield Scanner: An organic version of the City Scanner. Transports hopper mines into battlefields.
  • Strider: Large ground assault units used by the Combine. Striders walk on three long legs, towering over the battlefield.

Combine Combat Technology

The Combine employs numerous devices and weapons used in the day-to-day policing and surveillance of the general populace. Some of these are merely human inventions that have been re-designed by the Combine purposes better suit, while others are either original or re-designed technology of other civilizations.

  • Manhack: Essentially, a flying, autonomous circular saw capable of tracking targets.
  • Rollermine: A ball-shaped 'mine' with a rudimentary targeting system that, once activated, follows anything it identifies as a threat and subjects it to electric shocks. They can also attach themselves to vehicles such as the Scout Car.
  • Hopper Mine: A programmable explosive device that hops into the air and explodes when approached by an enemy.
  • City Scanner: A flying security camera and scout that takes pictures of enemies and relays their location to its command center. Also "dive-bombs" its target if subject to enough incoming fire. Occasionally used as a spotter for Striders.
  • Sentry Gun, Ceiling Turret, and Ground Turret: Programmable, autonomous sentry weapons.
  • APCs: The main mode of transport of Civil Protection, is a common sight within the cities. They are armed with a missile launcher and a mounted pulse rifle.
  • Hunter-Chopper: Piloted by two members of the Overwatch, this vehicle is primarily used to track down solitary members of the Resistance, or small groups of Resistance soldiers. Heavily armed and armored, it features a pulse cannon and can saturate an area with mines.
  • Razor Trains: Combine trains made to transfer Combine Troops, supplies, and prisoners to locations.
  • Headcrab Shell: Deployed onto resistance outposts and base areas. These are deployed more often in the Uprising. A common sight in City 17 and the Outland. It contains several Headcrabs of varying species.
  • Sky Shield: Referred to in Overwatch radio chatter, "Sky Shield" appears to refer to air units of the Combine. Overwatch soldiers report their target or are given a target through "Sky Shield."

Combine Architecture

Most examples of Combine structures are large and imposing, with very blocky, monolithic shapes with sharp angles made of dull, blue-gray metal. Various tubes, wires, and pipes can be seen running throughout gaps in the walls and down along corridors and tunnels. Their buildings are purely functional, with no thought given for comfort, embellishments or decorations. Limited usage of aesthetics include infrequent usage of Combine imagery such as signs or logos, and artificial brightness creating harsh, dark shadows throughout the Combine's complexes.

Steep, deep drops and lack of guardrails are in Combine complexes as well. This lack of railing and deep falls are likely due to the Advisors' ability to fly and thus not need bridges. Bridges are, however, in places where Combine soldiers move and operate; another example of the Combine's assimilation of human technologies. The material the Combine use for their constructs remains unknown.

  • The Citadel - The large skyscraper looking after City 17 and Combine forces serving as the main base of operations and the headquarters for the Combine.
  • The Depot - A building looking after prisoners at Nova Prospekt.
  • The Vault - A floating prison in City 17's Quarantine Zone used to store The G-Man.

Behind the scenes

  • The Combine originally was to use Earth's building materials and twist them to construct their buildings. This mix of materials resulted in odd designs, such as the Citadel's interior made out of ceramic tiles. The material mix became the more familiar building material used by the Combine in the final version.
  • Some Combine units were not from the final version of Half-Life 2 for various reasons, such as redundancy or unsatisfying gameplay. Some Combine subdivisions became into others seen in the retail version. These cut enemies include the Combine Assassin, Beta Combine Elites, Combine Sniper Elites, the Alien Assassin, and the Conscripts (Which become allies with the destroyed air exchange). Other cut enemies include Cremator, the Combine Guard, Combine Synth Elite Soldier, the Alien Combine Soldier, the Combine Super Soldier, Combine Mobile Mine, and the Sacktick.
  • During the E3 demo, the Citadel is called "the Combine." This name implies the Citadel could originally have been the Combine.
  • The Combine's name inspiration was likely by the 1962 Novel One Flew Over the Cuckoo's Nest by Ken Kesey. The novel's narrator mentions an oppressive, manipulative, and mechanistic authority that rules the masses, that he referred to as "The Combine."
  • The Combine was originally going to use scrapped HECU voice lines and cut during the making of Half-Life 2.

List of appearances


  1. 1.0 1.1 Half-Life 2: Raising the Bar
  2. 2.0 2.1 2.2 Breencasts
  3. Marc Laidlaw Vault on HalfLife2.net
  4. Half-Life 2 - as stated by the Overwatch Voice
  5. 5.0 5.1 PC Zone magazine, September 2005.
  6. Marc Laidlaw's e-mail on Xen, Planet Half-Life Mailbag.
  7. Half-Life 2 Walkthrough - Chapter 5: Black Mesa East. Planet Half-Life.
  8. Half-Life 2: Episode One. Chapter: Urban Fight
  9. Half-Life 2 on Steam