Half-Life: Opposing Force, an expansion pack for Half-Life by Gordon Frreman.

Half-Life: Opposing Force is an expansion pack for Valve Software's science fiction first-person shooter video game Half-Life. The game was developed by Gearbox Software and published by Sierra Entertainment on November 1, 1999. Opposing Force is the first expansion for Half-Life and was first announced in April 1999. Randy Pitchford, the lead designer on the game, later noted that he believed Gearbox was selected to develop Opposing Force because Valve wanted to concentrate on their future projects. Over the course of development, Gearbox brought in a variety of outside talent from other areas of the video games industry to help bolster various aspects of design.

Opposing Force returns to the same setting as Half-Life, but instead portrays the events from the perspective of a U.S. Marine, one of the enemy characters in the original game. The player character, Adrian Shephard, is sent in to neutralize the Black Mesa Research Facility after a scientific mishap causes it to be invaded by aliens, but quickly finds that the Marines are outnumbered and slowly being beaten back by a second alien race and black operations units. Opposing Force was received well by critics, many describing it as the new benchmark title for expansion packs, in a similar fashion to how Half-Life revolutionized the first-person shooter genre. Other reviewers, however, thought that the game still had many of the negative aspects of other expansion packs, although it was still regarded as an exceptional add-on.

Gameplay

As an expansion pack for Half-Life, Opposing Force is a first-person shooter. The overall gameplay of Opposing Force does not significantly differ from that of Half-Life: players are required to navigate through the game's levels, fight hostile non-player characters and solve a variety of puzzles to advance.[2] The game continues Half-Life's methods of an unbroken narrative. The player sees everything through the first person perspective of the protagonist and remains in control of the player character for almost all of the game. Story events are conveyed through the use of scripted sequences rather than cut scenes. Progress through the game's world is continuous; although the game is divided up into chapters, the only significant pauses are when the game needs to load the next part of an environment.[3] Opposing Force also features an extended multiplayer, incorporating the various new environments and weapons into the original deathmatch mode used in Half-Life.[4] After release, a new capture the flag mode with additional levels, items and powerups, was created by Gearbox for the game.[5]

For the most part the player battles through the single-player game alone, but is occasionally assisted by friendly non-player characters. Security guards and scientists will occasionally help the player in reaching new areas and convey relevant plot information. However, Opposing Force also features fellow U.S. Marines who will assist the player in combat to a far greater degree than security guards. Three types of Marines are featured in the game: the soldier will simply provide fire support for the player with a submachine gun, shotgun or machine gun, the combat medic is capable of healing the player and other non-player characters, while the engineer can cut through doors and remove obstacles, allowing the player and their squad to proceed unhindered.[6] A selection of enemies from Half-Life populate the game, including alien creatures such as headcrabs and Vortigaunts. A variety of new alien non-player characters, labelled "Race X", appear in the game as well, often engaging in combat with the aliens from Xen. The player also encounters human opponents in the form of a detachment of black operations units who have been sent to destroy the base in the wake of the failure of the U.S. Marines to eliminate the alien threat.[7] A limited selection of Half-Life's weaponry is allocated to the player to defend themselves with, although several new weapons such as a sniper rifle, combat knife and a variety of alien weaponry are also present in the game.[8]

[edit] Synopsis
[edit] Setting
Opposing Force is set in the same location and timeframe as that of Half-Life, taking place at a remote New Mexico laboratory called the Black Mesa Research Facility. In Half-Life, the player takes on the role of Gordon Freeman, a scientist involved in an accident that opens an inter-dimensional portal to the borderworld of Xen, allowing the alien creatures of Xen to attack the facility. The player guides Freeman in an attempt to escape the facility and close the portal, ultimately traveling to Xen to do so.[9] Opposing Force, however, shows the events of Half-Life from the perspective of a different protagonist. The player assumes the role of Adrian Shephard, a U.S. Marine Corporal assigned to the Hazardous Environment Combat Unit, a specialized unit sent in to Black Mesa by the government to quell the alien threat and silence all witnesses. However, after Shephard becomes isolated from his fellow Marines, he must ally with the Black Mesa personnel and attempt to escape the base.[7]

[edit] Plot

Opposing Force opens with Shephard riding on a V-22 Osprey with his squad. His squad discuss their deployment, somewhat irritated that they have not been told what they are being deployed for. However, as they are nearing their Landing Zone at Black Mesa, airborne alien creatures attack the Osprey formation, causing Shephard's Osprey to crash land. Shephard regains consciousness in a Black Mesa medical bay, tended to by the science team, learning that the Marines are being steadily beaten by the alien forces from Xen and orders have come through to pull out. Consequently, Shephard departs to reach an extraction point and escape the facility.[10] However, Shephard is prevented from reaching the extraction point by the enigmatic G-Man, forcing the evacuation craft to leave without him.

Other Marines who have also been left behind team up with Shephard and attempt to reach another extraction point near Black Mesa's Lambda Complex, but en route they come under attack from black operations units seeking to thoroughly contain the situation and eliminate all survivors.[11] Shephard makes it to the Lambda Complex alive, and briefly sees Gordon Freeman as the latter teleports to Xen in the final stages of Half-Life. To escape the teleportation chamber, Shephard is forced to enter a separate portal, briefly taking him to Xen before depositing him in an entirely different area of the facility. The facility is now heavily damaged, and it soon becomes clear that a new alien race, Race X, has exploited the situation to mount a localized invasion, attacking both human and Xen forces in Black Mesa indiscriminately.[12] Fighting between the black operations units and Race X quickly intensifies.

Shephard soon encounters more stranded Marine units in the wreckage of the base, and tries to break through the black operations units to reach an escape point past the facility's storage unit, but meets heavy resistance from both Race X and the black operations units.[13] A surviving Black Mesa security guard reveals to Shephard that the black operators intend to detonate a tactical nuclear weapon in the base, thereby totally sealing it off and killing everything in it.[14] After successfully neutralizing the guarding black operations unit, Shephard disarms the device and proceeds to the nearby storage areas, intent on escape. However, the G-Man rearms the device as Shephard departs. The storage unit has become a thick battleground between Race X and the black operation units, and although Shephard manages to evade them, he is informed by another security guard that something very large is coming through an alien portal blocking the exit path.[15]

At the portal, Shephard discovers a gene worm, a massive creature facilitating the Race X invasion. Shephard is able to kill the creature, but just afterwards he is teleported onto an Osprey by the G-Man. As the G-Man congratulates Shephard on his accomplishments, the nuclear device detonates in the background, destroying Black Mesa. The game closes with the G-Man detaining Shephard someplace where he can tell no one of what he has seen and cannot be harmed, pending further evaluation.[16]

[edit] Development
Half-Life: Opposing Force was first announced by developer Gearbox Software on April 15, 1999.[17] In their press release, founder Randy Pitchford stated that "our number one goal is to preserve the integrity of Half-Life and provide new experiences that expand upon the sensation of the original", and also announced that the expansion pack would allow the player to play as one of the soldiers featured in the original game.[17] The name Opposing Force has a double meaning, referring both to the fact that the player is now one of the enemies in the original game, as well as to Newton's third law of motion.[17] In a later interview, Pitchford stated that he believed that Valve Software offered Gearbox the chance to make a Half-Life expansion was from a wish "to focus on their future titles".[18] In addition, Pitchford commented that Valve and Gearbox had agreed not to "severely modify" the game engine used by Half-Life and Opposing Force as it "risks breaking all of the wonderful work" that the game's custom content community was creating.[18] Substantial information on Opposing Force's development direction, as well as new locations, characters and story were revealed at the 1999 Electronic Entertainment Expo convention.[19] The official website for Opposing Force, hosted by publisher Sierra Studios, was put online in July 1999.[20]

Over the course of the game's development, Gearbox acquired various outside talent to assist in designing some aspects of the game. In June 1999, Gearbox announced that the successful level designer Richard Gray would be assisting in developing the multiplayer aspects of the game.[21] Several other designers subsequently joined the project in September 1999, with collective experience from the development of Daikatana, Quake II, Doom and Shadow Warrior.[22] In the subsequent two months, media releases displaying a variety of screenshots were unveiled.[23] The game was released on November 1, 1999.[24] Gearbox later released a multiplayer update in May 2000, adding a new capture the flag mode to the game, along with various new items to accompany the new mode.[5] Opposing Force was later released on Valve Software's Steam content delivery system.[25] Opposing Force was also published as part of Sierra's Half-Life: Generation compilation in 2002,[26] and as part of Valve Software and Electronic Arts' Half Life 1: Anthology on September 26, 2005.[27]