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    Half-Life: Opposing Force

    Game » consists of 6 releases. Released Nov 19, 1999

    The first expansion to the 1998 first-person shooter Half-Life, showing the events of the Black Mesa invasion in a different perspective: from a commando of the antagonistic Hazardous Environment Combat Unit.

    Short summary describing this game.

    Half-Life: Opposing Force last edited by Nes on 03/25/20 10:57AM View full history


    Shepard, holding the Shotgun, and a friendly Medic
    Shepard, holding the Shotgun, and a friendly Medic

    Half-Life: Opposing Force is a sci-fi horror first-person shooter developed by Gearbox and published by Sierra for the PC on November 19, 1999 as an official expansion pack to Valve's 1998 game Half-Life.

    The first of two official expansions to Half-Life (the other being Half-Life: Blue Shift) and the first game by Gearbox, Opposing Force takes place during the main story of the original Half-Life (where the secretive Black Mesa Research Facility is being invaded by inter-dimensional aliens after an experiment gone wrong) and is played from a different perspective: as a commando of the antagonistic Hazardous Environment Combat Unit.

    Players assume the role of USMC Corporal Adrian Shephard, a member of the HECU (and silent protagonist) sent to the complex to quell the alien threat and eliminate all witnesses. After his squad's V-22 Osprey crash-lands and he is left behind during the HECU's mass evacuation, Shephard must navigate the complex to find a way out (fighting alien threats, both old and new, and hostile Black Ops units).

    While much of the game is the same as the original, it features numerous differences and additions, including a variety of new weaponry and enemies, an updated AI squad system (with soldiers that provide additional types of support), and a traditional body armor system (as Shephard does not have access to a HEV Suit used in the main game). In addition, the expansion adds additional maps and models to the original's multiplayer mode. The game later received an updated multiplayer "Capture the Flag" mode on June 8, 2000.

    A standalone version of the game was included with the North American release of the Half-Life: Blue Shift expansion, and was later digitally re-released by Valve (via Steam) as its own standalone product on September 12, 2003 (with support for Mac and Linux added later on July 31, 2013). The multiplayer portion of the game was included (as a bonus "mod") with international versions of Half-Life: Blue Shift, as well as the retail release for Half-Life: Counter-Strike.

    New Features

    In order for parts of the story to make sense, some weapons and even some enemies were entirely different, and replaced items from Half-Life. For example, the HEV suit was removed and replaced by Body Armour, which functions the same by makes sense when put in context of the story, Adrian Shepard would not have access to the same technology that Gordon Freeman would. The game also introduced new AI system, and a new type of Black Mesa guard, named Otis who, armed with Desert Eagle, provides significantly better support than " Barneys" who only had the basic pistol. Opposing Force's new interactive AI system allowed fellow troops, like Medics, to heal the player character and basic Soldiers would toss them ammo.

    New Weapons

    Pipe Wrench

    Pipe Wrench
    Pipe Wrench

    The Crowbar which became an icon of the Half-Life series was not actually taken up by Adrian Shepard, instead replaced by the Wrench. The Wrench is significantly slower than the Crowbar was, although much more powerful. In addition, the Wrench actually had an alternate fire, which readied the Wrench for a more powerful blow by winding it up for a moment. The Wrench is the first weapon Shepard obtains through the events of Opposing Force.

    Combat Knife

    Shepard actually gains an additional melee weapon along with his Wrench, a Combat Knife, which is actually less powerful than either the Crowbar or Wrench, but has a much faster attack rate. Additionally, if Shepard is able to sneak up on an unsuspecting enemy, the Knife should be able to deliver a one-hit kill.

    Desert Eagle

    The Colt Python of Half-Life was replaced with the more militaristic Desert Eagle. The two are quite comparable in terms of high-power, accurate weapons, but the Desert Eagle sacrifices the Python's zoom feature for a laser sight, triggered using the alternate fire button.

    Sniper Rifle

    Keeping with the military theme of Opposing Force, the Crossbow is replaced by a tactical bolt-action Sniper Rifle, which was quite similar, in many ways, to the Crossbow of the past. First introduced in the training sequence at the start of the game, it too featured a zoom feature for long-range enemy elimination.

    M249 SAW Light Machine Gun

    Another military weapon, Opposing Force features a SAW LMG, which has both a rapid rate of fire and massive clip size, and is quite useful for engaging multiple targets or laying down suppressive fire.


    The experimental weapon featured in Opposing Force appears to be some sort of portable teleporter, or some early attempt at one. However, Shepard uses this experimental technology for more macabre purposes, and uses it as a weapon. Its primary fire launches a portal torwards an enemy, and teleports them far away from Shepard, or destroys them (the technology is unstable, after all). It's alternate fire transports Shepard himself to Xen, for good or bad. Teleportation can either kill Shepard or help him move past an obstacle.


    This expansion also introduced a host of new Alien weaponry, including the Barnacle, which is essentially a hand-held version of the Barnacle enemy encountered many times in the game. Firing the barnacle launches it's long tongue at a target enemy, dragging it close and dealing damage until it is fully digested. It is also used as a method of travelling across otherwise inaccessible gaps, by attaching its tongue to specific, stationary spores and dragging the player closer to the targeted spore.

    Spore Launcher

    Speaking of Spores, another new Alien weapon was just that, a living weapon which fired spores at enemies. The spore launcher actually swallows the ammo fed into it, and spits out the explosive ammunition upon command. By holding down the alternate fire, the Spore Launcher charges up a shot before firing it. Spores actually bounce a bit if not targeted directly at an enemy, so take careful aim.

    Shock Roach

    Another living weapon, the Shock Roach is a giant bug that fires electricity at enemies. Like the Hive Arm it replaced, the Shock Roach regenerates ammunition up to eight shots, but each shot does less damage than the preceding one. It is not recommended firing this weapon underwater; it is instant death.

    New Equipment

    Body Armor

    Though it wouldn't make much sense for Adrian Shepard to be wearing the HEV suit worn by Gordon throughout Half-Life, the same system takes place, by charging Shepard's high-tech Body Armour, much in the same fashion one would charge the HEV suit. In fact, the Body Armor charges using either specifically Body Armour chargers or the more common HEV charging stations throughout the Black Mesa Facility.

    Night Vision

    Unlike the HEV suit, Shepard's Body Armor does not come equpped with a flashlight, and he must instead rely on his helmet and Night Vision to illuminate the darker corners of Black Mesa. The Night Vision is used in essentially the same way the flashlight was in Half-Life.

    Squad Management

    Opposing Force introduces a new AI system, and allows the player to have a squad of allied soldiers, who can assist in various situations and provide additional fire support. There are several different classes of soldiers, all of which are able to assist Shepard in various ways.


    Just a typical grunt, Soldiers are best used to provide additional fire and protection against the many hazards of Black Mesa. However, they can occasionally provide ammo to Shepard when needed.


    As the name says, Medics can provide healing in addition to standard soldier duties. This makes Medics one of the more valuable allies to have around, as they can keep Shepard healthy and happy. Occasionally, a Medic can be required to move the plot forward, if there is a soldier who needs medical attention in order to open a blocked path, though for the most part they are not necessary to keep around.


    Soldiers that carry a blow torch and supplies, these chain-smokers can break through otherwise inaccessible doors, either to advance the plot, or occasionally, to open up a secret area (usually by keeping them alive for a long period of time). If an Engineer encounters a door, he should automatically attempt to break through, unless there are enemies nearby that must be taken care of.


    Half-Life: Opposing Force builds on the online multiplayer component of the original Half-Life by adding 10 new player models and 13 new arenas. Later updates add an additional Capture the Flag mode, which overhauls certain aspects of the multiplayer component while adding new features (such as power-ups).

    New Player Models

    • beret
    • cl_suit
    • drill
    • fassn
    • grunt
    • massn
    • otis
    • recruit
    • shephard
    • tower

    New Maps

    • op4_bootcamp
    • op4_datacore
    • op4_demise
    • op4_disposal
    • op4_gasworks
    • op4_kndyone
    • op4_kbase
    • op4_meanie
    • op4_outpost
    • op4_park
    • op4_repent
    • op4_rubble
    • op4_xendance

    Capture the Flag

    The patch of the expansion, released on June 8, 2000, adds a new game mode: Capture the Flag. Similar to CTF modes in other games, Opposing Force Capture the Flag (or "OpFor CTF") pits two teams (the "Black Mesa" civilians and the "Opposing Force" soldiers) against each-other to steal the enemy flag (while defending their own) and bring it back to their base to earn points.

    Notable differences between this mode and standard deathmatch mode include:

    • Themed teams. Instead of using the player's chosen model and color scheme, players instead choose their character from a list prior to spawning.
    • Updated HUD. Each team now has a separate HUD color (orange for Black Mesa, green for Opposing Force) and the HUD now displays additional information (such as flag status). Targeting another player now shows their name and affiliation.
    • Updated weaponry. Players now start with the Pipe Wrench, .357 Desert Eagle, and Barnacle Grapple. A new alternate fire is added to the Barnacle Grapple that gives it slack (allowing players to rappel down walls). Flag carriers drop their flag while being teleported by the Displacer.
    • Power-Up items. Most maps now has five special Power-Up items that grant special bonuses to whoever claims them.
    • Endgame statistics (similar to GoldenEye 007). When the match ends, the game shows special statistics that displays various accomplishments from the match (including who is the MVP, who scored the most points, and who held each power-up the longest).

    Player Scoring

    In addition to the team score (based on the amount of flag captures), players have their own individual score used to determine their ranking in the match. Killing enemy players are counted separately.

    Players gain a point for:

    • Grabbing the enemy flag.
    • Returning the friendly flag manually.
    • Killing an enemy flag carrier.
    • Killing an enemy that is close to the friendly flag base.
    • Killing an enemy that recently damaged the friendly flag carrier.
    • Having an enemy flag captured shortly after returning the friendly flag manually.

    Players gain 10 points for being the one to capture the enemy flag.


    Most maps now have five Power-Ups that grant special buffs to a player when they claim them. Only one Power-Up at a time can be carried per player, and players can discard their Power-Up using the Throw Powerup key. Player-Ups remain on the player until they either discard it or they are killed.

    Players can view who has each Power-Up by bringing up the scoreboard. In addition, targeting players also brings up which Power-Up they have.

    • Accelerator (Red) - Increases the user's damage output (including self-damage).
    • Backpack (Yellow) - Gives the user ammunition (for every ammo type in the game). Automatically gives the user additional ammunition for their current weapon over time (with certain restrictions) while doubling the clip size of their current weapon.
    • Health (Green) - Automatically recharges the user's Health over time (2% per second) while increasing their maximum Health to 150%. If it's discarded while the user has over 100%, their Health slowly drains down to that value.
    • Jump Pack (Orange) - Allows the user to perform more powerful jumps by holding the Crouch key, then pressing the Jump key.
    • Shield (White / Blue for HUD) - Automatically recharges the user's Shield over time (2% per second) while increasing their maximum Shield to 150%. If it's discarded while the user has over 100%, their Shield slowly drains down to that value.


    Black Mesa (Orange)

    • Barney (barney)
    • Cleansuit Scientist (cl_suit)
    • Gina (gina)
    • Gordon Freeman (gordon)
    • Otis (otis)
    • Walter (scientist)

    Opposing Force (Green)

    • Squad Commander (beret)
    • Drill Sgt. Sharp (drill)
    • Grunt (grunt)
    • Recruit (recruit)
    • Adrian Shephard (shephard)
    • Pvt. Tower (tower)


    • op4ctf_biodomes - Black Mesa Biodomes
    • op4ctf_chasm - Chasm
    • op4ctf_crash - Crash Site
    • op4ctf_dam - Hydro-Electric Dam
    • op4ctf_gunyard - Gunyard
    • op4ctf_repent - Repentagram x2
    • op4ctf_mortar - Mortar
    • op4ctf_wonderland - The Wonderland
    • op4ctf_xendance - Xendance


    Half-Life: Opposing Force follows the character Adrian Shephard, one of the Marine Corps Hazardous Environmental Unit Commandos, who was sent in to exterminate everyone at Black Mesa Research Facility and the Lambda core, and ultimately to exterminate Gordon Freeman in particular. However, Shepard never really receives these orders; he is separated from his unit early in the offensive, and attempts to reunite with his squad for the first part of the game. He finally reconnects with his squad, but is left behind when the mass evacuation of the facility begins. Shepard, along with other soldiers left behind, attempt to find a way out of the facility, expressing their lack of enthusiasm for their orders.

    Shepard ultimately catches up with Freeman, and watches as he enters the Xen relay and escapes from Black Mesa. Shepard experiences the previously un-encountered Race-X, a species of alien who came to the facility after Freeman had left. He travels to Xen, like Freeman, and succeeds in navigating the hostile environment. Ultimately, Shepard encounters the mysterious G-Man, who compliments him on his resilience and adaptability in such dire circumstances. Unlike Freeman, the G-Man does not offer Shepard employment, and instead leaves him in stasis on a tram seemingly careening through outer space. Shepard's ultimate fate is unknown; he has not explicity died, but has yet to return to a later instalment of the series.

    Voice Cast

    • Jon St. John, the voice of Duke Nukem, lent his voice for senior drill instructor Dwight T. Barnes and various marines in the game.
    • Michael Shapiro is the voice of Barney Calhoun.
    • Harry S. Robins provided the voice for various scientists.

    System Requirements

    Minimum: 500 mhz processor, 96mb ram, 16mb video card, Windows 2000/XP, Mouse, Keyboard, Internet Connection

    Recommended: 800 mhz processor, 128mb ram, 32mb video card, Windows 2000/XP, Mouse, Keyboard, Internet Connection


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