From Combine OverWiki, the original Half-Life wiki and Portal wiki
Over the years, several retcons have been applied to the Half-Life and Portal series' storyline. Most of them are minor and were made by the developers to accommodate the subsequent games' storylines. They do not affect gameplay or the main plot.
- In Half-Life and its expansions, scientists and security guards are generic NPCs with only a few variations. Later, Valve and Gearbox based actual characters on these NPC types, sometimes also reusing their nicknames as the new character's name:
- The bald scientist model wearing thick framed glasses ("scientist01", or "Glasses") was turned into the character Walter Bennet for Blue Shift, a reference to Walter's World, a popular fan fiction set in the Half-Life universe created by Kevin "Fragmaster" Bowen on Planet Half-Life. Later, for Half-Life 2, the "Glasses" scientist was again turned in a character, this time into Isaac Kleiner, although it was not made clear if he was ever seen in person in Half-Life. Kleiner's first name was also retconned: in old documents from the Half-Life period, he is referred to as Alex, but in Half-Life 2 he is called Isaac.
- The African-American scientist model ("scientist03", or "Luther") was turned into the character Eli Vance for Half-Life 2. Eli is said to have lived at the Black Mesa Research Facility with his wife and daughter, although they are not seen or mentioned in Half-Life. Eli was retconned in Half-Life as being the scientist who sent Gordon for help right after the Resonance Cascade. In Black Mesa East, Eli tells Gordon after meeting him again: "The last time I saw you, I sent you up for help after the Resonance Cascade. I never thought it would take you this long to get back to me!"
- The Holographic Assistant and Half-Life Deathmatch’s player model, "gina.mdl", was turned into one of Half-Life: Decay’s two main protagonists, Gina Cross. In-universe speaking, that also made Gina Cross the woman who gave her likeness to the hologram.
- The generic "Barney" security guard model was turned into Blue Shift’s main protagonist, Barney Calhoun, and was established to be the security guard pounding on a door along the Sector C Line at the beginning of Half-Life, although Blue Shift retconned the fact that he already had his vest and helmet. He was later brought back for Half-Life 2 and its episodes as one of the main protagonists.
- The generic overweight "Otis" security guard model introduced in Half-Life: Opposing Force was turned into the character of Otis Laurey. However, he is only mentioned in the Half-Life PlayStation 2 instruction manual. Whether or not he is seen in-game is unknown.
- Barney says at the beginning of Half-Life 2 that he owes Gordon a beer. This is one of the random security guard sentences said prior to the Resonance Cascade in Half-Life. In Half-Life 2, it is implied that Barney actually said this at least once to Gordon back then.
- In an interview with series writer Marc Laidlaw and in The Half-Life Audio Script, the Administrator alluded to by the scientists is revealed to be the G-Man, suggesting he is the one overseeing the experiments. For Half-Life 2, the G-Man was retconned to be an independent entity, and Dr. Breen was created to retroactively fill the Administrator's role.
- The meal ruined in the microwave oven at the start of Half-Life was later said to belong to Dr. Magnusson.
- While older sources state that Gordon started work at Black Mesa only shortly before the incident, Half-Life 2 and Episode One indicate that Gordon had been working at Black Mesa long enough for Barney to owe him a beer and to race against him in the air ducts to open Kleiner's office whenever the doctor locked himself out of it. During a Breencast, Dr. Breen describes Gordon's time at Black Mesa as being a "brief tenure."
- Several changes made to the dates pertaining to Aperture Science originally given in the ApertureScience.com timeline were given by Game Informer in 2010 (they were written by Erik Wolpaw): "1978", the date for Cave Johnson's mercury poisoning, was changed to "1974". "1979", the date for Johnson's kidney failure, was changed to "1976". "1975", the date when Aperture Science ceased to produce only shower curtains, was changed to "1973". The last paragraph of the timeline was also expanded, stating that GLaDOS was activated in 1998 instead of the original "Several Years Later", and that a few days later the Black Mesa Incident occurred, thus placing Half-Life during the same year as its release, while it was known as "200-" in every source (in-universe documents featured in the instruction manuals). It was however stated later by Marc Laidlaw that "1998" was incorrect and that "200-" was indeed the proper date. The original ApertureScience.com timeline was further altered in Portal 2, for instance changing the cause and era of Johnson's illness to poisoning due to Conversion Gel instead of mercury.
- The Portal ending was changed (or rather, extended) in the March 3, 2010 update to the game. Instead of the original fadeout, Chell is now dragged away by the Party Escort Bot who tells her "Thank you for assuming the party escort submission position." It was made to "re-energize" Portal and bridge the gap between it and its sequel.
- Portal 2 features several retcons, aesthetic and factual. As for the aesthetic aspects, some elements of the Enrichment Center featured in the first Portal have been redesigned (other than being in a state of disrepair), such as the Vital Apparatus Vent, the elevators, the doors in the original Test Chambers, the corridors leading to GLaDOS' original chamber, and GLaDOS' design itself. As for the factual aspects, they mostly affect the history of Aperture Science, for instance the reason and era of Cave Johnson's poisoning.
- The Half-Life Story on Planet Half-Life (archived)
- Half-Life 2: Raising the Bar
- Interview with Marc Laidlaw on PC Gamer Online (archived)
- Half-Life Audio Script
- Half-Life 2: Episode Two commentary
- Half-Life instruction manual
- Half-Life PlayStation 2 instruction manual
- Aperture Science: A History on Game Informer
- Facts about the date issue on the Marc Laidlaw Vault on the ValveTime.net Forums
- Marc Laidlaw Vault on the ValveTime.net Forums
- GameInformer, April 2010 issue
- Exploring Portal’s Creation And Its Ties To Half-Life 2 on Game Informer
- Retcon on Wikipedia