List of Combine non-combat technology in Half-Life 2

This is a list of fictional non-combat technology employed by the Combine empire in Half-Life 2, a 2004 first-person shooter.

Overview

A common trait of Combine structural engineering seems to be making most of their creations resemble imposing, fairly featureless monolithic constructs, save for the odd irregular patterns that dot their surface. On the other hand, some seem to be unnecessarily complex, feature inefficient use of open space, while others exhibit properties that defy conventional physics.

The Citadel

Physical construction and overview

The Citadel is the structure from which The Combine maintain their iron grip upon City 17. Resembling a massive, metallic and largely featureless skyscraper; it rises several kilometers into the sky from ground level, and extends some distance underground. The Citadel is heavily mechanized, and entire sections can interchange to allow for mass deployment of airborne units such as scanners or gunships. It appears to either provide power to City 17 or drain power from it, as power lines can be seen extending out of it. These then join on to regular transmission towers and poles, connecting it to the rest of the city.

The Citadel has two known configurations depending on specific Situations. The first of these is likely an idle configuration, which is probably maintained when no serious threats are active. This configuration is signified by a single set of rib-like structures exposed within the right half of the Citadel, with an outer metal plating retracted slightly above the inner plating. However, shortly after Freeman is transported inside Doctor Breen's office in the Citadel during the malfunctioning of Dr. Kleiner's teleporter, the Citadel enters an alerted state. The Citadel can be seen changing its configuration as Barney gives Gordon a crowbar. The inner plating retracts upwards, exposing four sets of "ribs." A small piece of plating barely visible on the left of the Citadel also descends partly down the tower. The Citadel remains in this configuration for the remainder of the game. Thereafter an alarm sounds throughout City 17. It can be theorized that there are other configurations the Citadel may take in different situations, but these two are the only configurations depicted in the game.

As mentioned in Raising the Bar, entire blocks from City 17 vanished into thin air as the Combine Delivered the Citadel to Earth. There is a slight mention of this event in Dr. Breen's first speech in Half-Life 2, during which he states that the Citadel was "thoughtfully provided by Our Benefactors." The Citadel is embedded in a huge chasm appearing as if thrust into the earth forcefully from a high altitude. It is completely surrounded by enormous mobile walls which crush surrounding material and prevent access from the streets. Attached to the base of the Citadel are massive beams that repeatedly pound the earth, acting as giant restrictors to repel the underground antlions. In Half-Life 2 : Episode One, the dark fusion reactor's destruction ceases many of the Citadel's functions effectively allowing antlions to INFILTRATE City 17.

The number of Citadels in Earth remains unknown in game. It also is clearly visible that there are numerous other Citadel-like structures outside Earth, as seen through an off-world portal which Dr. Breen intends to enter during the final moments of Half-Life 2.

Lower levels

The first few chapters of Half-Life 2: Episode One, show much of the lower levels of the Citadel. No war factories or synth manufacturing plants are located in this area of the structure. The Citadel is extremely unstable with an orange glow sweeping throughout the structure in contrast to the cold blue prior to the reactor's detonation. Fires have spread across the structure and much debris from what's left of the upper levels is constantly falling down to the lower levels.

An emergency evacuation chamber is located in the lower levels of the Citadel. The room is significantly different from that of the rest of the Citadel, giving off an eerie red glow. The room seems to serve as an emergency evacuation chamber, allowing Combine Advisors to quickly escape in times where the Citadel is in peril. The Advisor escape pods are located under the glass floor of the room and when preparing to dock they rise up and move through a tube before positioning themselves in a chute and moving upwards.

Toward the very bottom of the Citadel is the core which is only accessible via a lift that descends several floors. The core chamber is protected by large blast doors bearing an insignia of a stylized version of the international symbol for radioactivity. A large control room is situated overlooking the core with a central access lift leading down to its chamber. Three rooms are located across the chamber which are specifically designed to help stabilize the core in the event that its energy output becomes unstable. The machines in these rooms form a threefold containment system that ensures that the intensity of the energy reaction within the core stays within safe limits. Connected onto the core itself is a train station where it's likely that Razor Train cargo is emptied. This point in the Citadel lies approximately one kilometer below the surface and extends throughout City 17 and beyond.

Central levels

The final chapters of Half-Life 2 exhibit the interior of the Citadel which contrasts its featureless exterior. Abundances of advanced technology are found within, ranging from energy orb raceways, raw energy contained within force fields, matter disintegration fields, to elevators and platforms that defy conventional gravity. The entire building is constructed from the same blue-black metal characteristic of all Combine structures. Confiscation fields remove all unregistered weapons and items from individuals apart from Combine soldiers, though unexpected reactions can occur within these fields to objects emitting a zero-point energy field.

There are railway systems within the Citadel that are used by Razor Trains to ship and deliver cargo such as Stalkers enroute from Nova Prospekt. Stalkers are delivered in pods, and the Citadel houses a large distribution and transportation system for these pods. Tasks such as the operation of basic panels, or the repairing of damaged Combine equipment and units is done by Stalkers, under the constant supervision of Overwatch personnel or scanners.

The Citadel houses large war factories, where Combine equipment, technology and weapons, as well as Synths are manufactured. Two types of Synth that were never encountered elsewhere during the main game, the crab synth and the mortar synth, can be seen being transported around on conveyor belts, indicating that they are manufactured in the Citadel, although this could only be a means of moving the synths throughout the large facility. The Citadel also provides a central hub for Overwatch soldiers (including Elites), who are present in overwhelming numbers, and is the launching point for gunships.

Upper levels

On one of the very top levels of the Citadel is Doctor Breen's office, believed to be the location from which he transmits his Breencasts. Unlike the rest of the Citadel, Breen's office has a more classical, human look to it, although Combine architecture is still a very dominating feature in the room. His office includes various luxury items such as a wooden desk, mantle clock, leather seat, globe, expensive carpeting, and busts of himself. His office also contains a large set of monitors, from which he can communicate with contacts such as a Combine Advisor. Breen's office is connected to the prisoner transport system used by Gordon Freeman, and there are many other prisoner pods around his office. Otherwise, more welcome guests can access the office via an elevator connected to the dark fusion reactor. It can be assumed that Breen lives in the Citadel as well as works in it.

The apex of the Citadel contains the Combine's dark fusion reactor, which is used to power their tunnelling entanglement device and allow them to tunnel into Earth from their universe. At the climax of Half-Life 2, the dark fusion reactor is destabilized and destroyed.

Destruction

In Episode One, the aftermath of Gordon's assault on the Citadel is clearly visible. The overloading of the Dark Fusion reactor had downed power and destabilized the structure of the whole building, and Gordon had to make his way to the core to re-engage the containment field and delay the core's inevitable meltdown. The Citadel is by this time barely occupied compared to its earlier state. There are however, several soldiers left, and a few Stalkers for operating machinery. The Citadel's interior now glows orange, in stark contrast to the cold blue it used to be when functional, while bridges are falling apart and debris continuously falls from the top of the tower. From the outside, the Citadel's peak is surrounded by swirling black and red clouds with green lightning bolts emerging. The power lines connecting the Citadel to City 17 are no longer present, and the explosion of the Dark Fusion reactor has blown the top of the Citadel off. The climax of Episode One is witnessed by Gordon and Alyx, when the Citadel's core suffers the inevitable meltdown as it collects the colossal amount of energy needed to send a final data transmission off-world to the rest of the Combine empire.

Aftermath

Half-Life 2: Episode 2 reveals the ruins of the Citadel, as Gordon and Alyx look out upon it from a distance. A nascent super-portal now occupies the space above the ruins of the structure, with a giant beam of energy flowing into it from what remains of the Core. The ruined Citadel is shown to be the epicentre of several Portal Storms throughout the game, which are shown as expanding waves of energy, originating at the ruins. It becomes the objective of the rest of the Episode to close the portal before more Combine are allowed to get through.

Throughout Episode Two the super-portal can be seen from a distance. However thanks to the efforts of the Resistance teams in the White Forest Rocket Facility, a rocket is launched which uses the old Black Mesa teleport network to close the super-portal.

Depot

The depot (as seen in Chapter 9, "Nova Prospekt") is an enormous structure towering over the Nova Prospekt prison facility. The depot is a nexus for Combine distribution of stalkers, as well as a storage center for political prisoners such as Doctor Eli Vance. The depot covers cellblocks C1 through D8, and fills the area with Combine articles. In addition, the depot is a relay for the Razor Trains as seen in Chapter 1 ("Point Insertion") and again at the bridge in Chapter 7. Basically, once humans arrive at the depot, they are held in sturdy metal straitjackets housed within metal pods. Once needed, the pods can be brought in at any point from within an access point. Just like the Citadel, the depot has its own pod distribution center. Finally, the depot houses the prototype Combine entanglement device, which in the end of Chapter 9 explodes just as Gordon and Alyx teleport out of the facility.

Command panels

Combine command panels are found throughout City 17, Nova Prospekt, and the Citadel, and have multiple purposes. The command panels found in City 17 are GeneRally used to open and close gates, and they may also be used for communication, as seen when Barney Calhoun communicated with Doctor Isaac Kleiner in the opening levels in the game. The majority of command panels found in Nova Prospekt are used to work the systems around the facility – such as gaining access to surveillance cameras or transporting prisoner pods. They are also used to work the teleporter that Doctor Judith Mossman helped build for the Combine. The command panels in the Citadel are only seen conveying Breencasts, while they probably possess other functions also. When looking closely at some of the modules, the words "Combine Maintenance Access Command Module" written in English can be seen.

Command panels can only be operated by Combine personnel. However, Alyx is seen using an EMP device to assume control of the panels. Barney has a limited Civil Protection clearance, which allows him to operate some, but not all of the panels. In short, Command panels can be seen as futuristic computers.

Heavy doors

Heavy doors can be found anywhere in the Citadel or Nova Prospekt, and correspond with a command panel or a standard Combine lock. It is unknown what sort of mechanical device transports such a large piece of equipment, but it is known that Combine doors are generally guarding something important like an elevator or pod access points. Although the Combine doors can usually only be opened by Overwatch soldiers, Alyx can open them with her EMP tool, and Barney can open some using command panels. Furthermore, heavy doors can activate alarms depending on their importance, like the Nova Prospekt Restrictors.

Bunkers

Seen mostly lining the coast to Nova Prospekt, Combine bunkers house soldiers and supplies. Provided mainly for defense against Antlions and other intruders, Combine bunkers are virtually bullet proof, with one to five mounted pulse guns, and a small entry/exit door at the rear of the building. Bunkers also house alarm switches. Also seen here are two bunkers connected to make one.

Door lock

A Combine door lock is a small, metallic device that is placed on a door instead of a door handle, and acts to keep the door locked in order to prevent unauthorized access. Locks are most commonly found in the residential apartments throughout City 17. This could possibly be because the Combine, in its oppressive nature, chooses when the citizens are allowed to enter or leave their apartments, and monitor everyone that walks in and out. It is evident that only Combine personnel may operate a lock, but Alyx can use her EMP device to override Combine locks in order to gain access to restricted areas, as she does in Nova Prospekt.

In Episode One, the door locks demonstrated the ability to self destruct, flashing red and emitting a beeping noise, then exploding, destroying the door they were attached to. This seems to have been used by Overwatch to forcefully enter buildings. The Combine use self destructing door locks in Episode 2 as well, in order to surprise and hopefully wound anyone on the other side of the door.

Defensive structures

These range from portable fixed-gun emplacements that can be set up in a minute to full-sized barricades cordoning off entire streets. Instead of windows, they bear some sort of forcefield that resembles a liquid in appearance and offers ample protection against weapons. The doors that the barricades have are multi-sectioned and mounted on mechanical arms.

Field bridges

Field bridges are Combine force-fields that act as a means of reaching otherwise inaccessible areas. Field bridges can only be activated if two power generators within the immediate vicinity are started. It is seen within the Citadel's core that field bridges can be bisected, and each half can rotate without the need for extra machinery at the new, broken end, to move into a specific position.It can only be activated by the combine power cores taken from the power streams found in the Citadel, and can be disabled as seen in Episode One by the Stalker.

Watchtowers

Watchtowers are found throughout City 17, usually near defensive structures, and act to give Combine personnel a better view of the streets. There is usually a single Civil Protection unit on top of the watchtower, who may fire a flare once a reasonable force of Resistance is spotted, as a signal to call backup. Although most watchtowers are inaccessible by normal citizens, some Resistance members in the game climb up into them using ropes, and drop supply crates found up there down on the streets for the player. There are several variants of watchtowers located around City 17 and its boundaries. One of the most notable variants is the watchtower located on the surface inside the perimeter of Nova Prospekt which resembles a battle tower or small radio tower, though the outdated construction suggests it is an original Nova Prospekt fixture and intended as a perimeter guard post. Watchtowers are also found along the rim of the compound surrounding the Citadel.

Forcefield generators

Scattered throughout City 17, the generators consist of two pylons, each one on either side of the path it is intended to protect. Invisible from a distance, the forcefield generated between the two pylons prevents entry of anything living that does not register with the system as being with the Combine, instead emitting a humming sound when in physical contact. However, other than vehicles driven by non-recognized personnel, the system will not block inanimate objects. Some of them are seen in-game being powered off standard human power supply sockets, Combine power generators, or from Combine APC batteries. They are placed at regular intervals along railway tracks in City 17.

Restrictors

Used to protect cities from invasion by antlions in the countryside, "Restrictors" (or "Thumpers" termed by Resistance members) are massive machines that repeatedly pound the ground using a set of metal beams. The vibrations generated keep Antlions away from the local area; however, they can be deactivated by pressing the power button located near the base of the machine.

Restrictors guarding the perimeter of Nova Prospekt are far larger than the ones found along the coastlines. They are twice the height of a standard Restrictor with their power buttons elevated half way up the height on a platform. These sport a built-in ladder leading to the upper platform, have spotlights, have a wider vibration range, and trigger a public warning system if deactivated.

Power generators

Combine generators are mainly found within the Citadel, but can also be found in certain locations in City 17, such as the Overwatch Nexus or the Plaza in the "Anticitizen One" chapter of Half Life 2. The generators are used to power devices such as gates and locks, or weaponry - like the suppression device. There are many more generators in the Citadel than anywhere else, supplying power to systems in the immediate area such as forcefields.

In appearance, the generators look similar to large cylinders, with a solid base and top and liquid sides, like those seen on defensive structures. The generator has a core with orbs floating within, which create a beam of electricity that runs from the top to the bottom of the generator. The energy orbs are the actual objects that generate the power, as when they're knocked out (by the Gravity Gun, for instance), the generator will cease to function (however, if a free-moving orb is near enough to a module, the generator can actually draw it in to resume power generation). Generators powering critical systems typically have about three orbs inside them, but ones that power smaller devices will have just a single orb. There are special generators found only in the Citadel, which can have a limitless amount of orbs cycling through them, and seem to be orb transport paths of some sort.

Anyone unlucky enough to step into or to be thrown inside a generator will be disintegrated, just as they would be if they got hit by an orb launched from a pulse rifle. The orbs launched from the pulse rifle appear to be identical to those in the generator, so it is likely that the Combine "package" such orbs into ammunition which can be launched by the pulse rifle. However, the orbs from the generators appear orange instead of white, and are much more powerful; capable of damaging or destroying vehicles and synths. A generator lacking an orb will "capture" an orb fired at it by a Gravity Gun or Overwatch Pulse rifle.

In the Valve Hammer Editor, the protective field that keeps the power orbs inside the generators can be removed, allowing it to float freely through the room. By jumping directly on top of the orb, the user can actually bounce into the air. The faster the movement for the orb, the higher the user is bounced.

In Episode One, another type of generator has appeared, resembling a wall socket. They are seen mostly in the lower levels of the Citadel and act as "system activation nodes", allowing the player to start equipment such as field bridges or the core's containment devices. This type of power generator can be activated by launching an energy orb into its center, causing its four arms to retract inwards to hold it in place and begin to siphon energy from it. Two of these generators need to be operational if field bridges are to be activated.

The energy socket used by the Combine is similar in function and appearance to the Aperture Science High Energy Pellet Energy Socket from the Aperture Science Enrichment Centre, although whether there is any connection or not is unknown.

It should be noted that Stalkers will attempt to deactivate this type of generator by destroying the energy orb with their lasers.

Mobile walls

Seen surrounding the Citadel and certain areas of Nova Prospekt, mobile walls are actually machines, using powerful drive systems in tandem with heavy metal blocks to slowly expand outward and destroy existing structures in the way. Standard operation is to lift and force a set of blocks outward, before allowing them to drop, and then alternating with another set. This is believed to be the Combine's method of harvesting raw materials for other purposes such as Synth creation and the construction of other vehicles.

Razor Trains

Large, relatively featureless and imposing; Razor trains are custom-built to work on human rail networks. Taller than standard locomotives, their ramlike, sliver-thin appearance and all-black finish add to the threatening look of the fast-moving vehicle. Perhaps the most disconcerting aspect of the Razor Train is its horn: a distinctive, discordant bellow that announces the train's arrival and sounds more like a wounded animal than an air horn. They have ladders leading up to a compartment where the driver's compartment should be, supporting the idea that there is a crew. However it is seen in Episode One, how Alyx is able to program the train so its possible they are automated and are not driven by an engineer. One particular function they serve is to transport humans to Nova Prospekt, the Combine-controlled prison/laboratory, and transport completed Stalkers and Overwatch Soldiers to the Citadel.

Ration dispenser

Seen in action in the City 17 train station at the start of the storyline, window-mounted Combine ration dispensers serve to supply citizens with packaged food supply, given through a tray that slots out of the machine. More often than not, citizens are required to wait in front of the machine for several minutes to receive their rations. Besides its fundamental function, little else is known about these devices. According to the citizens, the food is not good at all, as quoted by some citizens: "I dunno about you, but I'm ready to join Civil Protection just to get a decent meal," and "You gotta be [...] hungry to wait in line for this crap."

It becomes obvious as the game progresses that food is used as both a carrot and a stick by the Combine, with increases promised for informing on potential "anticitizens"; conversely, those suspected of conspiracy against the Combine have rations reduced as a form of punishment. The threat of loss of food (with agriculture and livestock presumably devastated as a result of years of Combine rule and the antlion invasion, the only alternative food sources being birds, leeches and headcrabs) is clearly an effective way of keeping the population in check. It is said that citizens have been stripped of the right to even grow their own food.

Overwatch

Overwatch (voiced by Ellen McLain) functions as a dispatcher for Civil Protection as well as a public address and public warning system. Appearing to be a non-sentient "dumb" AI speaking with an upper-class English accent, Overwatch addresses Civil Protection via their comm. radios and to everyone via a public address system and seems to extend a vast network within City 17, Nova Prospekt and the interiors of the Citadel. Overwatch transmits messages, alerts, warnings, updates and broadcasts over an open comm. channel. Only intended recipient units appear to respond to broadcasts sent over the comm. Overwatch effectively keeps all units up-to-date. Whenever a CP unit is downed, Overwatch will notify all units over the unit's comm. radio. Messages heard over the unit's comm. will inform other CP units of "lost bio-signal for Civil Protection team unit" in a distinctive flat, clinical tone. Other messages heard include "lost bio-signal for protection team unit XRAY 9", or "unit down at Jurisdiction Block 514, remaining units contain", or alternatively "Unit down at zone 5-14; all teams, respond code 3".

Overwatch offers significant insight into the inner workings of the Combine, as it uses a type of medically-inspired Newspeak to describe resistance activity in the context of a bacterial infection and treatment. Additionally, some announcements display the coercive and violent tactics used by the Combine to ensure conformity:

• It is announced soon after the start of Route Kanal that "inaction is conspiracy", ordering residents to turn in Gordon Freeman. Food credits are deducted from humans as punishment for what is termed "inactive coercion".

• Freeman is progressively referred to as "staph invasion." Instructions are issued to CP units to 'inoculate', 'pacify', 'expunge', 'clamp', 'contain', 'administer', and 'sterilize.' His 'implicit citizenship' (the title is presumably a play on the totalitarian state's absence of legal guarantees) is revoked due to his "civil malcompliance" and "multiple anti-civil violation." Freeman is then addressed as "individual," and declared "malignant" status. When the Overwatch soldiers are introduced and the resistance movement is in full rebellion, she euphemistically orders them to "treat" and "amputate" rebels.

• It is announced near the start of Water Hazard that "judgment waiver" is in effect, allowing Civil Protection to deal with humans as they see fit.

• Gordon is referred to as "Anticitizen One" starting roughly around Water Hazard, and retains this designation until the end of the game. As Gordon progresses within Nova Prospekt, the announcer refers to him once as "Anticitizen Freeman", the first and apparently only time he is referred to by name by Overwatch.

Overwatch's disjointed speech, similar to that of telephone banking systems, and ability to apparently broadcast to more than one location at once, sometimes overlapping actively spoken broadcasts suggests it is a non-sentient artificial intelligence system possibly with pre-recorded messages and alerts. Overwatch broadcasts appear to emanate from the Citadel, although it appears to also be possible to broadcast announcements to specific areas.

Judging from some broadcasts, it seems as if Combine soldiers and CP units are to obey orders issued from Overwatch. When Gordon goes through a containment field in the Citadel, soldiers are told they are to "Deploy", "diagnose", and are ordered to "dissect." Within Nova Prospekt, Overwatch threatens of "permanent off world assignment/relocation" as punishment of failure. This threat is not limited to soldiers, however; near the end of "Point Insertion," Overwatch has also been heard threatening ordinary citizens with the same punishment for disobedience to Civil Protection officers, or aiding others in doing so.

In Episode One, the tone of Overwatch within the Citadel changes drastically. The voice is slowed and sounds sluggish. This new tone adds to the feeling that the Citadel's functions are failing, and supports Overwatch is likely an AI of some sort. Alerts "Warning bypass detected" and "Deploy, diagnose, deploy, diagnose, present singularity, present singularity" and other various messages are endlessly looped and integrated into others. When Freeman goes through a containment field, the same alert when Gordon first went through a containment field is played, which implies most, if not all of Overwatch's messages are pre-recorded and broadcasted where appropriate. Overwatch can be heard broadcasting throughout the city towards the climax of Episode One.

It should be noted that the Overwatch's voice changes dramatically in Episode Two; compared to the previous games, the voice sounds more menacing, yet somehow more human. However, the tone of the voice changes randomly like that of the AI GLaDOS in the Valve game Portal. This may be due to the destruction of the Citadel, from which it is generally assumed the Overwatch voiceovers originate.

Spotting scope

Featured only once in Half-Life 2, during the player's trek along the coastline, the Combine spotting scope is a telescope-like device that is used by the Combine to observe a Resistance outpost (New Little Odessa) from the other side of a bay (the scope is also notable for allowing the player to witness the G-Man meeting Colonel Odessa Cubbage). Little else is known of the device.

See also

• List of humanoid and synthetic Combine in Half-Life 2

References

• Half-Life 2 (PC), Valve Software, 2004. Official Website
• Half-Life 2: Raising the Bar, David Hodgson, Prima Games. ISBN 0-7615-4364-3
• Half-Life 2: Prima Official Game Guide, David Hodgson, Prima Games. ISBN 0-7615-4362-7

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