Half Life 2: Episode One

Half-Life 2: Episode One is a first-person shooter video game, the first in a series of episodes that serve as the sequel for the 2004 Half-Life 2. It was developed by Valve Corporation and released on June 1, 2006. Originally called Half-Life 2: Aftermath, the game was later renamed to Episode One after Valve became confident in using an episodic structure for the game. Similar to Half-Life 2, Episode One also uses the Source game engine. The game debuted new lighting and animation technologies, as well as AI sidekick enhancements.

The game's events take place immediately after those in Half-Life 2, in and around war-torn City 17. Episode One follows scientist Gordon Freeman and his companion Alyx Vance as they fight in humanity's continuing struggle against the transhuman race known as the Combine. When the story begins, Gordon wakes up outside the enemy's base of operations, the Citadel, after being left unconscious from the concluding events of Half-Life 2. During the course of the game, Gordon travels with Alyx as they attempt to evacuate the city. As the game comes to an end, Gordon and Alyx are caught in a major accident, and both of their fates are revealed in the sequel, Episode Two.

Valve views episodes One through Three as tantamount to a standalone release. Episode One is available as part of a bundle package known as The Orange Box, which also includes Half-Life 2, Episode Two, Team Fortress 2, and Portal. Episode One received a generally positive critical reaction, and the co-operative aspects of the gameplay received particular praise but its short length was criticized.

Gameplay
In Episode One players make their way through a linear series of levels and encounter various enemies and allies. The gameplay is broken up between combat-oriented challenges and physics-based puzzles. Episode One integrates tutorial-like tasks into the story to familiarize the player with new gameplay mechanics without breaking immersion. A heads-up display appears on the screen to display the character's health, energy, and ammunition. Throughout the course of the game, the player accesses new weapons and ammunition that are used to defend the character from enemy forces. Unlike in Half-Life 2, where Gordon's initial weapon is the crowbar, Gordon first acquires the Gravity Gun, which plays a crucial role in the game by allowing the player to use physics to manipulate objects at a distance in both combat and puzzle-solving scenarios.

The AI for Alyx Vance, Gordon's companion, was designed specifically for co-operative play in Episode One to complement the player's abilities. The developers described Alyx's programming for Episode One as a "personality code" as opposed to an "AI code", emphasizing the attention they gave to make Alyx a unique and believable companion. For part of the code, she was specifically programmed to avoid performing too many mechanical or repetitive actions, such as repeating lines of dialogue or performing certain routines in combat situations. Examples of this co-operative gameplay include combat in underground levels. In this scenario, the player can conserve their ammunition by using a flashlight to help Alyx spot and kill oncoming enemies. Similarly, Alyx will often take up strategic positions and provide covering fire to keep the player safe while they travel to a certain area or perform certain actions.

Setting
The original Half-Life takes place at a remote laboratory called the Black Mesa Research Facility. The player takes on the role of Gordon Freeman, a scientist involved in an accident that opens an inter-dimensional portal to the world of Xen and floods the facility with hostile alien creatures. After the player guides him in an attempt to escape the facility and close the portal, the game ends with a mysterious figure who offers Freeman employment. The protagonist is subsequently put into stasis by this mysterious character known as the G-Man.

Half-Life 2 picks up the story, in which the G-Man takes Freeman out of stasis and inserts him on a train en-route to City 17 an indeterminate number of years after the events of the first game, with Earth now enslaved by the transhuman forces of the Combine. The player guides Gordon to aid in humanity's struggle against the Combine and its human representative, Dr. Wallace Breen. He oversees the occupation from his base of operations in the Citadel, a monolithic building at the heart of City 17. Fighting alongside Gordon is an underground resistance led by former colleague Dr. Eli Vance, as well other allies including Dr. Vance's daughter Alyx Vance and the enigmatic Vortigaunts, an alien species. Half-Life 2 ends with a climactic battle atop the Citadel that inflicts critical damage to its dark fusion reactor. When it seems as if Alyx and Gordon are to be engulfed by the explosion, the G-Man appears once more. After giving a cryptic speech, he extracts Gordon from danger and places him in stasis once again.

Plot
Episode One begins after the explosion of the reactor from which Gordon was extracted by the G-Man and where Alyx Vance was left behind. Time suddenly freezes, and several purple Vortigaunts appear and rescue Alyx from the blast. After she is rescued, the Vortigaunts appear before the G-Man and stand between him and Gordon. They teleport Gordon away from the scene, much to the G-Man's displeasure.

D0g retrieves Gordon out from under some junk outside the Citadel, and Gordon reunites with Alyx, who is relieved to see him. Alyx contacts Eli Vance and Isaac Kleiner, who have escaped the city, and is informed the Citadel's core is at risk of exploding at any moment. Kleiner states the explosion could be large enough to level the whole of City 17, and the only way for them to survive is to re-enter the Citadel and slow the core's progression toward meltdown. Eli reluctantly agrees when he sees no other option (Undue Alarm).

Alyx and Gordon re-enter the now-decaying Citadel to try to stabilize the core; Gordon is successful in re-engaging the reactor's containment field, which delays the explosion (Direct Intervention). Alyx discovers the Combine are deliberately accelerating the destruction of the Citadel to send a "transmission packet" to the Combine's homeworld. She downloads a copy of the message, which causes the Combine to prioritize them as targets. Alyx also downloads a transmission from Dr. Judith Mossman, in which she mentions a "project" she has located, before being cut off by a Combine attack. Afterwards, Alyx and Gordon board a train to escape the Citadel.

The train derails en-route, forcing the duo to proceed on foot (Lowlife). As they fight through the disorganized Combine forces and rampant alien infestations, Kleiner appears on the screens Breen once used to pass out propaganda, and gives out useful updates to the evacuating citizens about the latest turn of events as well as reiterating the Citadel's imminent collapse (Urban Flight). Alyx and Gordon eventually meet up with Barney Calhoun and a group of other survivors who are preparing to move on a train station to escape City 17. Alyx and Gordon provide cover for the passengers as they board (Exit 17).<sup class="reference" id="cite_ref-16">

To keep the survivors safe, Alyx and Gordon opt to take a different train.<sup class="reference" id="cite_ref-17"> They manage to escape just as the reactor begins to detonate; the energy sends out the Combine's message.<sup class="reference" id="cite_ref-18"> Several pods containing Combine Advisors are ejected from the Citadel as it detonates. The resulting shockwave catches the train, derailing it. The last thing the player hears is the twisting of metal and Alyx whispering "...Gordon." The fate of Alyx and Gordon is revealed in Half-Life 2: Episode Two.

Development
Half-Life 2: Episode One is the first in a trilogy of episodes serving as the sequel of the 2004 first-person shooter video game Half-Life 2.<sup class="reference" id="cite_ref-19"> In February 2006, Valve announced that they would be releasing a trilogy of episodes covering the same story arc. While the plots and dialogue of Half-Life and Half-Life 2 were written solely by Valve's in-house writer Marc Laidlaw, the Half-Life 2 Episodes were collaboratively written by Laidlaw, Chet Faliszek, and Erik Wolpaw, with Laidlaw retaining overall leadership of the group.<sup class="reference" id="cite_ref-authorship_20-0">

Valve explained that the focus of Episode One was character development, in particular that of Gordon's female sidekick and friend Alyx, because she accompanies the player for virtually the entire game.<sup class="reference" id="cite_ref-21"> Project lead Robin Walker discussed the reasoning behind this approach in an article announcing the game in the May 2005 issue of PC Gamer UK, saying, "It's kind of ironic that despite so much of the theme of Half-Life 2 being about other characters and other people, you spent most of the game alone."<sup class="reference" id="cite_ref-pcgamermay_22-0"> Lead writer Marc Laidlaw expanded further on the game's premise, saying, Episode One deals with the events and issues set in motion during Half-Life 2. You've done critical damage to the Citadel. The whole place is going to go up, taking out City 17 and what's in its immediate radius. You and Alyx are leading the flight from the city getting up close and personal with some of the creatures and sights from the end of the game.<sup class="reference" id="cite_ref-pcgamermay_22-1"> It was later confirmed that players would reprise the role of Gordon Freeman, unlike the original Half-Life expansion packs, which all dealt with different characters. Valve decided to develop Episode One in-house, as opposed to working with outside contractors as with previous expansions, because the company was already comfortable with the technology and construction tools of Half-Life 2.<sup class="reference" id="cite_ref-23">

Because of Alyx's significant involvement in the game, Valve made modifications to her AI that allowed her to react to the player's actions. Modifications include commentating on objects the player manipulates or obstacles they have overcome. She also acts as an important device in both plot exposition and directing the player's journey, often vocalizing what the player is required to do next to progress.<sup class="reference" id="cite_ref-dvd_24-0"> The developers explained that a large part of their focus was creating not only a believable companion for the player, but also one that did not obstruct the player's actions. They wanted to allow the player to dictate his/her own pace and method of overcoming any challenges faced without being hindered. This meant that Valve often had to scale back Alyx's input and dialogue during the player's journey so they would not feel pressured to progress and consequently object to her presence.<sup class="reference" id="cite_ref-dvd_24-1"> The developers also placed what they described as hero moments throughout the game, which allow the player to single-handedly overcome obstacles such as particularly challenging enemies, during which Alyx takes the role of an observer and gives the player praise and adulation for their heroic feats.<sup class="reference" id="cite_ref-dvd_24-2"> Play testers were used extensively by the developers throughout the entirety of the game's creation in order for Valve to continually gauge the effectiveness of in-game scenarios as well as the difficulty.<sup class="reference" id="cite_ref-opening_the_valve_25-0">

The game runs on an upgraded version of Valve's proprietary Source engine, and features both the engine's advanced lighting effects, and a new version of its facial animation/expression technology.<sup class="reference" id="cite_ref-opening_the_valve_25-1"> Upgrades to enemy AI allow Combine soldiers to utilize tactics previously unavailable to them. For example, Combine soldiers were given the ability to crouch while being fired upon in order to duck underneath the player's line of fire.<sup class="reference" id="cite_ref-dvd_24-3"> The game's soundtrack was composed by Kelly Bailey.<sup class="reference" id="cite_ref-authorship_20-1"> The music is used sparingly throughout; it plays primarily during scenes of major plot developments or particularly important action sequences such as large battles or when encountering a new enemy.<sup class="reference" id="cite_ref-dvd_24-4">

While no new locales were introduced in Episode One, large alterations were made to the appearance of both City 17 where the game takes place and the Citadel from the end of Half-Life 2 to reflect the changing shape of the world and remind the player that their actions have major effects on the story line.<sup class="reference" id="cite_ref-26"> The Citadel has degenerated from the cold, alien, and imposing fortress of the previous game into an extremely unstable state. This provides a visual cue to the player of the catastrophic damage they inflicted, and it allows for the introduction of new gameplay elements that accentuate the dangers which come with the Citadel's imminent collapse. In addition, it serves a thematic purpose by highlighting the weakening of the Combine's dominance in City 17. Likewise, City 17 has been altered to reflect the aftermath of the resistance's open rebellion, with vast swathes of destroyed buildings, and the introduction of foes previously kept outside its confines in Half-Life 2 to emphasize the scale of the uprising.<sup class="reference" id="cite_ref-autogenerated1_27-0">

Critical Reception
Upon release, Episode One was sold in both retail stores<sup class="reference" id="cite_ref-34"> and Valve's online Steam distribution system, where it was sold at a discount price.<sup class="reference" id="cite_ref-35"> The game was also distributed by Electronic Arts as both a standalone release and as part of Half-Life 2: Platinum Collection.<sup class="reference" id="cite_ref-36"> It was available for pre-load and pre-purchase through Steam on May 1, 2006, with Half-Life Deathmatch: Source and Half-Life 2: Deathmatch immediately available for play as part of the package.<sup class="reference" id="cite_ref-37"> Episode One is available as part of a bundle package known as The Orange Box, which also includes Half-Life 2, Episode Two, Team Fortress 2, and Portal; and is available for Mac, PC, Xbox 360, and PlayStation 3.<sup class="reference" id="cite_ref-nextgenconfirmation_38-0"> <sup class="reference" id="cite_ref-gamespotorange_39-0"> About 1.4 million retail copies of Episode One were sold by 2008.<sup class="reference" id="cite_ref-40">

Response to Episode One was generally positive, and reviewers praised the game for having more intricate, well-paced gameplay than Half-Life 2.<sup class="reference" id="cite_ref-Gamespotrev_8-2"> <sup class="reference" id="cite_ref-avrev_41-0"> The game's interactivity, particularly in the form of Alyx and her reactions to the player's actions and the events of the game, was also singled out for praise.<sup class="reference" id="cite_ref-Gamespyreview_31-1"> PC Gamer commented that "while this inaugural episode may not be the essential FPS that Half-Life 2 is, I can't imagine any shooter fan who'd want to miss it."<sup class="reference" id="cite_ref-pcgamerusreview_33-1"> In its review, PC Gamer UK directed particular praise to the balance between puzzle-oriented and action-oriented challenges throughout the game.<sup class="reference" id="cite_ref-pcgameruKreview_3-3"> In Australia, the magazine PC Powerplay awarded the game 10 out of 10.<sup class="reference" id="cite_ref-pcpowerreview_42-0"> Edge praised the "deftness" with which the game was able to direct the player's eyes, and the strength of Alyx as a companion, concluding, "In an interactive genre bound to the traditions of the pop-up gun and invisible hero, it simply doesn’t get more sophisticated than this."<sup class="reference" id="cite_ref-edgereview_30-1"> Episode One earned a scores of 87/100 and 85.59% on review aggregators Metacritic<sup class="reference" id="cite_ref-metacritic2_29-1"> and GameRankings respectively.<sup class="reference" id="cite_ref-gamerank_28-1"> IGN awarded Episode One with the title of "Best PC FPS of 2006" and described it as a "great bang for the buck using Valve's new episodic plan", although it did not offer "the complete experience that Half-Life 2 was".<sup class="reference" id="cite_ref-IGN1_43-0"> GameSpy ranked Episode One ninth on its 2006 "Games of the Year" list, and it also noted the implementation of Alyx as a believable and useful companion.<sup class="reference" id="cite_ref-Gamespy2006GOY_44-0">

A common criticism of the game is its short length. Episode One takes roughly 4–6 hours to complete, which raises the issue of whether the game justifies its price.<sup class="reference" id="cite_ref-Gamespotrev_8-3"> Computer Games Magazine argued the futility of reviewing the game due to its episodic nature; as the first part of a three-part story arc, it is difficult to judge it when divorced from the final product.<sup class="reference" id="cite_ref-cgmreview_45-0"> Game Revolution expressed disappointment at a lack of new features such as environments and weapons.<sup class="reference" id="cite_ref-Gamerevolutionreview_2-2">

Links

 * 1) "Half-Life 2: Episode One review". GameSpy.
 * 2) "Half-Life 2: Episode One". IGN.
 * 3) "Half-Life: Episode One on Metacritic". Metacritic.
 * 4) "Half-Life 2: Episode 1 Review". Edge.
 * 5) "Episode One review". GameSpot.
 * 6) Official Half-Life 2: Episode One website
 * 7) Combine OverWiki, an external Wiki