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Half-Life 2: Episode One is the first of a planned trilogy[1] of expansion packs/episodes for the 2004 first-person shooter game, Half-Life 2. The episode takes place immediately after the end of Half-Life 2, in the war-torn setting of City 17. The player is forced to deal with the effects of their actions during the main game. The episode is a stand-alone game; while a continuation of Half-Life 2, it does not require the original game to be installed or registered to a user's Steam account to play. It takes advantage of several major upgrades to the Source engine since the release of Half-Life 2, primarily its high dynamic range rendering capabilities and the upgraded facial animation system.

Episode One was released together with Half-Life Deathmatch: Source, a port of the original Half-Life's multiplayer, which doubles as Episode One's multiplayer component. The retail copies of Episode One also come with Half-Life 2 Deathmatch for those who have not previously purchased the later title.


Taking place in City 17, just after the events of the last game, Half-Life 2: Episode one again follows scientist Gordon Freeman and his friend Alyx Vance as they stabilize a damaged Citadel core to buy time before it explodes, which will destroy the city and the surrounding area. They then rush to make it out of a war-torn City 17 as quickly as possible and also help evacuate any remaining citizens left.


Episode One's focus is on character development, in particular that of Gordon's female sidekick and friend Alyx Vance, to the extent that she accompanies the player for virtually the entire game:[2] "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," project lead Robin Walker said in the episode's announcement article in PC Gamer UK.

The announcement article also saw Marc Laidlaw explain the game's premise:

"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."

Despite this comment and much fan speculation, the Combine Crab and Mortar synths were not present in Episode One; Stalkers and previously glimpsed areas of the Citadel are instead encountered and explored by the player.

After some initial confusion, sparked partly with an attempt at humor by PC Gamer UK, which suggested that Alyx was Episode One's playable character, it was confirmed that players would indeed play as Gordon Freeman – unlike the original Half-Life expansion packs, which all dealt with different characters. Part of the reason for this change of direction may lie with the in-house development of Half-Life 2: Episode One: previously, Half-Life expansions were developed by third party Gearbox Software (albeit with scripts produced by Valve).

The game runs on an incrementally upgraded version of Valve's proprietary Source engine, and features both the engine's high dynamic range rendering capabilities, and a new version of its facial animation/expression technology. It also features the commentary node system debuted in the Lost Coast tech demo.

The renaming of Aftermath to Episode One[3] was an indication of Valve's confidence with their episodic structure, an implication confirmed in February[4] and May[5] of 2006, with news of a trilogy of episodes covering the present 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" are collaboratively written by Laidlaw, Chet Faliszek and Erik Wolpaw with Laidlaw retaining overall leadership of the group.[6]



Behind the scenes and Trivia[]

Half-Life 2 Aftermath cover

Concept cover for Aftermath

HL2 Aftermath wordmark

Aftermath wordmark.

Gman Vortigaunts prologue

Vortigaunts rescue Gordon Freeman from the G-Man's clutches.

  • The game was originally named Half-Life 2: Aftermath, but was renamed to Episode One after planning to make the game episodic.
  • Valve's Marc Laidlaw and David Speyrer take us behind the scenes of Episode One's development
  • With Dr. Breen's absence, Dr. Kleiner has hijacked City 17's public address system, appearing on TV screens throughout the game and keeping the Resistance updated with information about the Combine:
    • All Citizens are told to evacuate City 17 as quickly as possible, for while the Citadel's Core is currently stabilized, the Combine will eventually succeed in making it go critical once again, and when that happens, all of City 17 will be destroyed.
    • Humorously, Dr. Kleiner informs humans already out of City 17 that, due to the suppression field being disabled, now would be "an excellent time for procreation", and urges citizens to "do their part for the revival of the species". Alyx replies to this by asking, while glancing at Gordon, "is Dr. Kleiner really telling everyone to... get busy?"
    • The destruction of the Citadel's Dark Fusion Reactor has caused a chain reaction that has put a damper on the entire Citadel Reactor Network, effectively cutting them off completely from the rest of the Combine. However, Dr. Kleiner states that it is only a matter of time before communication is re-established; warning that "In addition to the completely xenotheric species, there are many modified post-human allies (Overwatch Soldiers) still remaining on Earth who will be doing their utmost to re-establish lines of communication and supply with the larger forces."
    • And lastly, Dr. Kleiner hints that the Resistance has made "secret technological advances" that may have long-lasting benefits in the war against the Combine.
Ep1 citadel advisors room advisor breen leaving1

A Combine Advisor.

  • The group of Vortigaunts in the game's opening scene are part of the "third power" at which Valve hinted;[7] their role and purpose are mysterious.
  • According to Marc Laidlaw[8][9], when the Vortigaunts intervene, they have a way of winding time back a little bit. So when they enter the scene, they rewind events to just before the G-Man has his way, and extract Gordon and Alyx from the G-Man’s clutches.
  • The G-Man's loss of control to the Vortigaunts is reinforced by his complete absence from the game thereafter. While he appears at least once in most of Half-Life 2's chapters, he is not seen at all in Episode One. Neither, notably, are Vortigaunts, but Combine Advisors are seen at several points on various video screens, tracking the player and Alyx from their theft of the Combine's data packet onward. The G-Man is also, for the first time ever, without his signature briefcase during the opening scene.
  • This is the first game in the series in which Gordon does not start on a train or tram. Somewhat similar scenes are experienced, however, during the slide of the thrown van entering the Citadel and the final train ride out of City 17.
  • A conversation between two Resistance soldiers can be overheard in which Dr. Kleiner and other main characters are criticized. One of the soldiers states that he "kind of misses the Combine" and Dr. Breen's show. The remark "it seems like everyone's a doctor but me" is also made.
  • A reference is made in dialog by two Resistance members to the fight that Gordon took part in at New Little Odessa. Their talk suggests that Odessa later took credit for being the one to destroy the Gunship, and that Gordon was never mentioned as being there or was said to have done nothing.
  • An often unnoticed addition to the Half-Life series' gameplay made in Episode One is the new change in Combine Soldiers' AI. Episode One's soldiers crouch more often than in Half-Life 2, and have the ability to crouch while being fired upon in order to "duck" underneath the player's line of fire, for the first time in the series. This feature is showcased to the utmost for the first time in the large street battle the player progresses through before entering the rebel safehouse in the game's fourth chapter.
  • An unnamed weapon, nicknamed Black Hole Grenade or Vortex Hopwire, can be used by using console codes.
  • One of the most infamous Achievements in The Orange Box is "The One Free Bullet"; to acquire it, players must complete Episode One having fired exactly one bullet in their entire run-through. This leaves the player using only the Gravity Gun, crowbar, rocket launcher, and grenades.
  • A glitch in the game can cause Alyx to die by the combine energy balls/secondary fire on the Pulse Rifle. It can also happen in Undue Alarm, and Alyx will disintegrate near the lift. The game will not fade out, but the player will not be able to start the lift anymore.
  • In the chapter Direct Intervention, when the player noclips to Judith Mossman's arctic base, the player can see Dr. Kleiner's Corkboard and the Mark V HEV Suit specs in the far end of the hallway where Judith is filming.
  • The Shotgun animation for Alyx, and other female resistance fighters, is greatly improved. It has a higher pumping rate, and does not have to aim first, which allows them to fire the shotgun while being attacked by enemies; however, for the male fighters, it still remains the same. It also has a newer reload animation; however, this does not apply for Combine Soldiers.

Critical reception[]

Critical and public response to Episode One was broadly positive, with some reviewers praising the game for having more intricate, well-paced action than the acclaimed Half-Life 2,[10] though a common critique of the game has been its short length;[11] depending on the player's skill (or patience) the game can take less time to complete than the company line of 4–6 hours, which has caused various observers to raise the issue of whether it justifies the price tag.[12]

The game's interactivity, particularly in the shape of the character of Alyx, has also received praise.[13]

PC Gamer magazine gave an 85% in the US edition and 90% in the UK edition to the game. In Australia, the magazine PC Powerplay awarded the game with a rarely seen 10/10. Edge gave the game 8 out of 10, praising the "deftness" with which the game was able to direct the player's eyes, and the strength of Alyx as a companion.[14]


  • Episode One received the "Best First-Person Shooter" of 2006 award from IGN.[15]



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External links[]

Ia icon Official Half-Life 2: Episode One website (Archived)
Steampowered favicon Half-Life 2: Episode One on the Steam Store
Game Guides
HeadCrab Union Game Guide
GameSpot Game Guide
Eurogamer's Episode One Preview
GameSpot Q&A
1UP.com exclusive Half-Life 2: Episode One preview
Official Half-Life 2: Episode One videos and trailers
Gamer Within's Episode One Review
Half-Life 2: Episode One Review - BytePress
Review on VGRC.net 8.75/10
Half-Life 2: Episode 1 Critique (Google Video, 45 min.)
Half-Life 2: Episode One Review (The Ant Nest)