Half-Life 3 - The Rise, Fall & Rebirth

| Summary status | complete |

Overview

This is a chronological retrospective of Half-Life 3 from the 1999 registration of halflife3.com through Episode Three’s cancellation, the 2015 Source 2 project, the 2021 HLX prototype, and 2024 Deadlock datamines. Tyler’s thesis is that “Half-Life 3” has named several different projects: a contractual placeholder after the Prospero games were dropped, the Episode Three trilogy, a 2015 Source 2 build, and the later HLX prototype. Most of the runtime recaps public interviews, magazine reports, leaks, and datamines rather than presenting new documents. Tyler is confident on the documented record and flags his main inferences: the “Old Man” G-Man sculpt, the Sephilon correspondence, HLX’s start date, and the Deadlock asset attribution.

Mentioned events

halflife3.com registration and the Sierra/Prospero contract

• Description: On June 28, 1999, Valve registered halflife3.com and halflife2.com (transcribed “Halflife22.com”). Tyler ties this to Valve’s Sierra publishing contract, public since the 2003 net-café lawsuit, which originally committed Valve to Half-Life plus Prospero 1 and Prospero 2. With Prospero abandoned, he argues the obligation was likely converted into three Half-Life games. He notes Counter-Strike was retailed as “Half-Life: Counter-Strike” to satisfy the contract despite having nothing to do with Half-Life.
• Confidence: Mixed — the registration and the public contract are documentary; the claim that the contract was renegotiated into three Half-Life titles is Tyler’s inference (“likely changed over”).
• Category: Business/legal
• Source: Domain registration records and the 2003 net-café lawsuit contract, as described by Tyler.
• Earlier mentions: None identified in this video.
• Verification: verified for the domain and contract; needs follow-up for the contract-conversion claim.

Gabe Newell rules out Half-Life 3 in 2003

• Description: In a June 13, 2003 interview with the Trepid mod team, conducted by Jonathan Day and Jesse Davis, Gabe Newell was asked whether Half-Life 3 might soon follow Half-Life 2 from “the proverbial back burner.” He answered, “No.” He also said Valve would “recharge a bit on short fun projects” after Half-Life 2 and that the team had little trouble deciding what to push next.
• Confidence: Fact — direct published Q&A.
• Category: Development state
• Source: Trepid fan-site interview with Gabe Newell, June 13, 2003.
• Earlier mentions: None identified in this video.
• Verification: verified — the named interview can be checked.

Game Reactor’s “Half-Life 3 world exclusive”

• Description: On March 18, 2004, the Nordic gaming magazine Game Reactor ran the headline “Valve reveals Half-Life 3 world exclusive,” claiming that a Gabe Newell interview showed Valve had begun sketching ideas for a third game. Tyler says the story was later debunked by Newell.
• Confidence: Fact — the headline and its subsequent debunk are documented; the original claim was false.
• Category: Marketing
• Source: Game Reactor magazine, March 18, 2004, and Newell’s later denial.
• Earlier mentions: None identified in this video.
• Verification: verified — the magazine and denial can be checked.

Microsoft’s Xbox 360 keynote lists Half-Life 3

• Description: At Microsoft’s August 1, 2005 Xbox 360 keynote, a PowerPoint slide mapping game engines, games, and companies listed Valve Software and “Half-Life 3.” CVG reported on the slide. Tyler presents it as an official Microsoft document rather than a Valve announcement.
• Confidence: Fact — official Microsoft presentation as reported by CVG.
• Category: Marketing
• Source: Microsoft Xbox 360 keynote slide, reported by CVG on August 1, 2005.
• Earlier mentions: None identified in this video.
• Verification: verified — the CVG report and slide image are named.

Episode One press release promises a trilogy by Christmas 2007

• Description: Half-Life 2: Aftermath was renamed Half-Life 2: Episode One. When Episode One went gold, Valve’s May 24, 2006 press release called it “the first in a trilogy of episodes that will conclude by Christmas of 2007.” Tyler says only Episodes One and Two had been discussed officially before that release.
• Confidence: Fact — official press release quoted directly.
• Category: Release date
• Source: Valve press release, May 24, 2006.
• Earlier mentions: None identified in this video.
• Verification: verified.

Eurogamer describes the episodes as “Half-Life 3”

• Description: In a Eurogamer interview with Gabe Newell and Erik Johnson (dated June 6 in the transcript, contextually 2006), Newell described the three episodes as Half-Life 3 in all but name: “Half-Life 3, aka episodes 1 to 3, is about the relationship with the G-Man.” He said the trio formed one arc about the G-Man losing control of the player and that Gordon Freeman would be the protagonist in all three.
• Confidence: Fact — direct interview quotes.
• Category: Development state
• Source: Eurogamer interview with Gabe Newell and Erik Johnson, conducted by Tom Bramwell.
• Earlier mentions: None identified in this video.
• Verification: verified; the printed year needs follow-up because the transcript says 2003.

Game Informer: Episode Three ends the trilogy, not the franchise

• Description: In an August 25, 2006 Game Informer interview by Billy Berghammer (transcribed “Billy Burghhammer”), Doug Lombardi said the new Portal protagonist would “have a role in Half-Life games in the future” and that Episode Three would end the trilogy but “not ending Half-Life, just the trilogy.”
• Confidence: Fact — published interview.
• Category: Lore
• Source: Game Informer interview with Doug Lombardi, August 25, 2006.
• Earlier mentions: None identified in this video.
• Verification: verified.

Valve Hardware Day shows Episode Three NPCs

• Description: At Valve Hardware Day on November 1, 2006, Valve demonstrated multi-core and multithreaded technology with a demo called Source Particle Simulation. The leaked build contained two NPCs later said to have been developed for Episode Three: NPC Blob, a coordinated swarm of snarks treated as one NPC, and NPC Surface, the blob-like “blobulator” that splits apart and recombines. Footage appeared in Danny O’Dwyer’s documentary; the build was restored and repacked by XJR9000 of the hl2-beta.ru forums.
• Confidence: Mixed — the demo, build, and entities are documented artifacts; the “developed for Episode Three” attribution is asserted without a named source in the transcript.
• Category: Technology
• Source: Leaked Source Particle Simulation build; Danny O’Dwyer documentary footage; XJR9000 repack.
• Earlier mentions: None identified in this video.
• Verification: verified for the demo and entities; needs follow-up for the Episode Three assignment.

PC Gamer’s Arctic base theory for Episode Three

• Description: A May 9, 2007 PC Gamer Episode Two preview repeated the theory that Episode Three would be set at the Arctic base seen in Episode One and would feature the cut Arctic battle described in Raising the Bar. When the writer put the theory to Doug Lombardi, Lombardi smiled and said, “That would be exciting, wouldn’t it?”
• Confidence: Fact — published preview and quote.
• Category: Lore
• Source: PC Gamer Episode Two preview, May 9, 2007.
• Earlier mentions: None identified in this video.
• Verification: verified.

Eurogamer: Episode Three pre-production and no return to City 17

• Description: In a May 17, 2007 Eurogamer interview, Doug Lombardi said Episode Three pre-production was “definitely going” and would ramp up as Episode Two wound down, with a “skeleton crew” splitting attention between the two. Co-director David Speyrer (transcribed “David Spair”) said a lot of work had gone into “creating a natural progress of topography and climate” and that he did not think players would return to City 17 in Episode Three.
• Confidence: Fact — direct quotes in a named interview.
• Category: Development state
• Source: Eurogamer interview with Doug Lombardi and David Speyrer, May 17, 2007, by Tom Bramwell.
• Earlier mentions: None identified in this video.
• Verification: verified.

Kikizo: Episode Three as a resolution

• Description: In an August 28, 2007 Kikizo interview, Gabe Newell said Episode Three would be “a resolution to a lot of things,” that players would feel closure on several threads while new questions opened, and that Aperture Science would be explored further: “Whether or not it shows up like in episode 2 or a different vehicle, we’ll definitely learn more.”
• Confidence: Fact — published interview.
• Category: Lore
• Source: Kikizo interview with Gabe Newell, August 28, 2007.
• Earlier mentions: None identified in this video.
• Verification: verified.

Games for Windows: Episode Three groundwork and the Orange Box reassignment

• Description: In a December 2007 Games for Windows magazine feature, Valve said the Episode One team had “leapfrogged ahead on episode 3 pre-production,” but that Valve later moved that group onto all three Orange Box games because Episode Two’s scope made that more valuable. Valve said it had “laid some groundwork for episode 3” without locking itself in.
• Confidence: Fact — on-record Valve statements.
• Category: Development state
• Source: Games for Windows magazine Valve feature, December 2007.
• Earlier mentions: None identified in this video.
• Verification: verified.

Games for Windows: Eli Vance stays dead; G-Man answers planned

• Description: The same December 2007 feature included Gabe Newell saying Eli Vance was permanently dead (“No, he’s dead. He really is dead”) and David Speyrer saying Valve would address the G-Man’s motivations and origins but wanted to do so obliquely rather than stating “he’s X and his motivation is Y.” Newell also acknowledged the risk of letting the G-Man mystery run too long.
• Confidence: Fact — direct quotes.
• Category: Lore
• Source: Games for Windows magazine, December 2007.
• Earlier mentions: None identified in this video.
• Verification: verified.

Source SDK update leaks three Episode Three files

• Description: On April 21, 2008, the Source Engine SDK was updated to the Orange Box branch and three Episode Three .cpp files were found: npc_combine_armored, npc_weapon_scanner, and weapon_proto1. A Valve employee told the Steam forums they were “leftover stuff that aren’t used and no longer exist” included “by mistake.” Tyler notes not all three had been scrapped at that point.
• Confidence: Fact — files in a public SDK plus a named Valve response.
• Category: Development state
• Source: Source SDK Orange Box update, April 21, 2008; Valve employee statement on the Steam forums.
• Earlier mentions: None identified in this video.
• Verification: verified.

E3 2008 exhibitor list includes Episode Three

• Description: Before E3 2008, the ESA’s public game list included Half-Life 2: Episode Three. Valve immediately debunked the listing.
• Confidence: Fact — public ESA list and Valve denial.
• Category: Marketing
• Source: ESA E3 2008 game list; Valve’s public denial.
• Earlier mentions: None identified in this video.
• Verification: verified.

PC Gamer’s Episode Three concept art and Into the Pixel

• Description: On July 10, 2008, PC Gamer acknowledged it had printed an Episode Three concept-art piece in its November 2007 Orange Box issue. The public found it through the 2008 Into the Pixel contest, and PC Gamer then showed a second piece it had been “saving for a rainy day.” All three pieces were on the Into the Pixel site by October 13, 2008.
• Confidence: Fact — magazine acknowledgment and contest gallery.
• Category: Marketing
• Source: PC Gamer, July 10, 2008; Into the Pixel 2008 gallery.
• Earlier mentions: None identified in this video.
• Verification: verified.

Kikizo: the next Gordon game will take longer

• Description: In an October 2008 Kikizo interview, Doug Lombardi said the next game starring Gordon Freeman would take longer to arrive than the gaps between Half-Life 2 and Episode One or Episode One and Episode Two, and that Valve might show something “at the very end of the year.” He defended the episodic strategy as an alternative to another six-year, roughly $40 million Half-Life 2-scale project.
• Confidence: Fact — published interview.
• Category: Development state
• Source: Kikizo interview with Doug Lombardi, October 2008.
• Earlier mentions: None identified in this video.
• Verification: verified.

Blue crowbar image traced to a 2004 film

• Description: A blue-crowbar image circulated from the Hidden Source mod forums, posted by a user called “the Christ” and hosted on Panther 37, and was read as an Episode Three tease. Tyler says it was concept art by Chris Thing (as transcribed), made for the French film Immortal (2004), with the crowbar and HUD added afterward; he says the image appears in the film. The transcript dates the post December 21, 2008.
• Confidence: Mixed — the image and its film source are checkable; the artist attribution is Tyler’s.
• Category: Marketing
• Source: Hidden Source forum post; Immortal (2004); Tyler’s attribution.
• Earlier mentions: None identified in this video.
• Verification: needs follow-up — confirm the artist and the film frame.

G4 interview: “very good reasons” for Episode Three silence

• Description: In a June 11, 2009 G4 interview about Left 4 Dead 2, Doug Lombardi and Gabe Newell repeatedly declined to discuss Episode Three. Newell said there were “very good reasons why we’re not talking about episode 3, which I can’t talk about yet,” while acknowledging fan frustration about the gap.
• Confidence: Fact — on-camera interview.
• Category: Development state
• Source: G4 interview, June 11, 2009.
• Earlier mentions: None identified in this video.
• Verification: verified.

Steamcast: Episode Three as “a victim of our willingness to experiment”

• Description: In an August 12, 2009 Steamcast interview, Gabe Newell described Valve’s varying release rhythms — Team Fortress 2 every six to eight weeks, Left 4 Dead yearly, Half-Life episodes on a third rhythm — and said, “EP3 is sort of … a victim of our willingness to experiment.” He promised to talk when Valve had something ready.
• Confidence: Fact — published interview.
• Category: Development state
• Source: Steamcast interview with Gabe Newell, August 12, 2009.
• Earlier mentions: None identified in this video.
• Verification: verified.

Edge retrospective: the last public “Episode 3” mention

• Description: In a March 2010 Edge retrospective on Half-Life 2, Gabe Newell discussed scaring players and said Valve had drifted from genuinely frightening them, musing about an older Episode Three audience facing “the death of their children” and “the fading of their own abilities.” Tyler calls this the last time Valve publicly said the name “Episode 3.”
• Confidence: Mixed — the Edge quotes are documented; the “last time” claim is Tyler’s own count.
• Category: Lore
• Source: Edge magazine retrospective, March 2010; Tyler’s analysis of later public statements.
• Earlier mentions: None identified in this video.
• Verification: needs follow-up — a complete search of Valve’s public statements after March 2010.

Portal 2 event cancellation and the “surprise” hoax

• Description: Valve cancelled its June 14, 2010 Portal 2 event at the Regal Theater two weeks out, announcing in an Aperture Science voice that it would be replaced by a “surprise.” The internet read the surprise as a Half-Life announcement; a pamphlet image and a VG247 Source 2 rumor spread. Gabe Newell replied to Half-Life 2.net with a one-word denial: “No.”
• Confidence: Fact — the cancellation notice and Newell’s denial are documented; the Half-Life interpretation was a fan hoax.
• Category: Marketing
• Source: Valve/Aperture Science cancellation notice, June 2, 2010; VG247; Half-Life 2.net email from Newell.
• Earlier mentions: None identified in this video.
• Verification: verified.

Alien Swarm tools expose the “Blob” entity

• Description: Alien Swarm launched on July 21, 2010 with mod tools that exposed an entity/info-node called “Blob.” Tyler identifies it as the Episode Three blobulator.
• Confidence: Mixed — the Blob entity is in the shipped tools; the identification with the Episode Three blobulator is Tyler’s.
• Category: Development state
• Source: Alien Swarm SDK/tools, July 21, 2010.
• Earlier mentions: References the blobulator/NPC Surface shown at Valve Hardware Day, covered earlier in this video.
• Verification: verified for the Blob node; needs follow-up for the Episode Three identification.

Episode Three snow textures recognized in Valve files

• Description: Tyler says snow textures from Episode Three had long been present in Valve’s files, but were only recognized as Episode Three assets a few months before this video. He does not name the files or the discovery.
• Confidence: Mixed — the textures exist in Valve files; their Episode Three origin and recent recognition are community claims without a named artifact in the transcript.
• Category: Development state
• Source: Community file analysis, as described by Tyler.
• Earlier mentions: None identified in this video.
• Verification: needs follow-up — the specific texture files and their project attribution.

The weaponizer was an Episode Three weapon

• Description: In a September 15, 2010 PC Gamer interview, Gabe Newell said the “weaponizer” whiteboard was an internal design experiment that had not seen the light of day, not an Episode Three weapon; Erik Johnson added that it must have dated from earlier design experiments. Tyler says they were wrong: the weaponizer was from Episode Three, and it appears briefly in the Noclip documentary’s gameplay footage.
• Confidence: Mixed — the contemporaneous denial is documented; Tyler’s correction rests on documentary footage.
• Category: Development state
• Source: PC Gamer interview, September 15, 2010; Noclip Half-Life documentary footage.
• Earlier mentions: None identified in this video.
• Verification: needs follow-up — frame-by-frame identification of the weaponizer in the documentary.

Gabe Newell: “The episodic model failed”

• Description: In a May 9, 2011 Develop interview, Gabe Newell said, “The episodic model failed.” He said Valve’s design and release philosophy had moved to entertainment-as-a-service, shorter cycles, and continuously updated platforms, with Team Fortress 2 as the model.
• Confidence: Fact — direct quote.
• Category: Business/legal
• Source: Develop magazine interview, May 9, 2011.
• Earlier mentions: None identified in this video.
• Verification: verified.

Portal 2 SDK leaks the Combine Adviser boss code

• Description: Around May 14, 2011, the Portal 2 SDK began rolling out and included “Combine Adviser Roaming” code left over from Episode Three, where the player would have fought a Combine Adviser in a boss battle — the Adviser that kills Eli. Tyler says the code was left in by accident after Episode Three had stopped being touched.
• Confidence: Mixed — the SDK code is documented; the boss-fight design is inferred from the file names and behavior.
• Category: Development state
• Source: Portal 2 SDK beta files, May 2011.
• Earlier mentions: None identified in this video.
• Verification: verified for the code; needs follow-up for the boss-fight design.

Dota 2 client datamine reveals Episode Three weapons

• Description: On September 19, 2011, an incomplete Dota 2 client build circulated and was datamined. It contained Episode Three weapon code: an ice gun, the weaponizer with concrete, liquid, and metal modes, and a flamethrower.
• Confidence: Fact — datamine of a real Valve build.
• Category: Development state
• Source: Datamine of the incomplete Dota 2 client, September 19, 2011.
• Earlier mentions: None identified in this video.
• Verification: verified.

Matt Charlesworth’s “Old Man” sculpt

• Description: In October 2011, Valve artist Matt Charlesworth posted a 3D sculpt titled “Old Man” to his portfolio. Tyler identifies it as the G-Man model for Episode Three.
• Confidence: Speculation — the upload is real, but the G-Man/Episode Three identification is Tyler’s inference.
• Category: Development state
• Source: Matt Charlesworth portfolio upload, October 2011; Tyler’s analysis.
• Earlier mentions: None identified in this video.
• Verification: needs follow-up — artist confirmation or a match to game assets.

Anonymous voice actor claims Episode Three work

• Description: On December 9, 2011, an anonymous voice actor claimed to have worked on Episode Three. John Patrick Lowrie, the voice of the Team Fortress 2 Sniper and Half-Life 2 male citizens, said, “No Half-Life 3 stuff yet. Haven’t heard anything,” and added that he and Ellen McLain had heard nothing about a new Half-Life episode. Tyler treats the anonymous claim as unconfirmed while allowing that some voice work may have occurred.
• Confidence: Mixed — the denials are on record; the anonymous claim is unverified.
• Category: Development state
• Source: Anonymous voice-actor claim; John Patrick Lowrie and Ellen McLain public comments.
• Earlier mentions: None identified in this video.
• Verification: unverified for the anonymous claim.

The leaking of the “Valve employee handbook”

• Description: On April 21, 2012, the “Valve employee handbook” leaked. Tyler says it was not a real handbook but a developer-marketing document written by a few employees, also delivered as a Greg Coomer keynote, containing Half-Life 3 jokes. He notes the first major Valve layoffs came less than a year later.
• Confidence: Mixed — the document exists; Tyler’s characterization of its purpose is asserted.
• Category: Business/legal
• Source: Leaked Valve “handbook”; Greg Coomer keynote; Tyler’s account.
• Earlier mentions: None identified in this video.
• Verification: needs follow-up — Valve confirmation of the document’s origin.

Episode Three concept art found on an artist’s Picasa portfolio

• Description: On June 27, 2012, Episode Three concept art surfaced from a Valve artist’s personal Picasa portfolio, where it had been posted in 2008 and sat for four years. A small Facebook gaming group found it, ValveTime amplified it, and the artist quickly removed it.
• Confidence: Fact — the portfolio and art are documented.
• Category: Development state
• Source: Artist’s Picasa portfolio, uploaded 2008; rediscovered June 27, 2012.
• Earlier mentions: None identified in this video.
• Verification: verified.

Source 2007 source code leak

• Description: On August 11, 2012, the full Source 2007 engine source code leaked, including complete versions of the Episode Three files weapon_proto1, armored combine, and the weapon scanner. Tyler says he and a mod team got them working in a mod called Half-Life 2: Aftermath.
• Confidence: Fact — the leaked source code is a primary artifact; the mod claim is Tyler’s own.
• Category: Technology
• Source: Source 2007 source-code leak, August 11, 2012.
• Earlier mentions: None identified in this video.
• Verification: verified for the leak; the mod is checkable through the linked project.

FGD files for Episode Three and Stars of Blood leak

• Description: On February 18, 2013, valveleakware.com posted FGD entity-definition files for Episode Three and the project Stars of Blood. FGDs define entity behavior for the level editor. Tyler says the files revealed substantial information about the then-canceled game; their origin is unknown, and the theory that they came from a leaked Source Filmmaker build does not hold because known builds do not contain them.
• Confidence: Fact — leaked files; Tyler explicitly says the origin is unknown.
• Category: Development state
• Source: valveleakware.com leak, February 18, 2013.
• Earlier mentions: None identified in this video.
• Verification: verified for the files; needs follow-up for provenance.

June 2013 Jira leak: a 43-member Half-Life 3 group

• Description: On June 19, 2013, Valve’s internal Jira project list was briefly public. It showed an Episode Three group, an Episode Three movie group (a Source Filmmaker short, not a film), and a Half-Life 3 group with 43 members. Tyler says the Half-Life 3 group corresponds to the procedural-generation Half-Life 3 discussed in The Final Hours of Half-Life: Alyx.
• Confidence: Mixed — the Jira listing is documented; the identification with the procedural project comes from a later book.
• Category: Development state
• Source: Leaked Valve Jira project list, June 19, 2013; The Final Hours of Half-Life: Alyx.
• Earlier mentions: None identified in this video.
• Verification: verified for the listing; needs follow-up for the group’s identity.

John Patrick Lowrie’s mocap comments and retraction

• Description: In August 2013, John Patrick Lowrie wrote in blog comments that Half-Life 3 was “not being worked on at this time as far as I know,” citing mocap as a design obstacle: filmed motion makes characters less able to track the player than Half-Life 2’s look-at system. He then told CVG he had misspoken and should not have commented, saying voice actors are “the last to know anything.” Tyler says Half-Life 3 was in development at that point.
• Confidence: Mixed — the statements and retraction are documented; Tyler’s counter-claim is inference.
• Category: Development state
• Source: Lowrie blog comments, August 2013; CVG follow-up.
• Earlier mentions: None identified in this video.
• Verification: needs follow-up — production evidence for 2013.

October 2013 Jira leak: Half-Life 3 splits into subgroups

• Description: On October 2, 2013, the Jira list was exposed again. The Half-Life 3 project had grown and split into art, audio, and core-team subgroups. Tyler says such subgroup formation indicates the game was in “hard legitimate development,” but that it did not last.
• Confidence: Mixed — the leaked structure is documented; the development-stage interpretation is Tyler’s.
• Category: Development state
• Source: Second leaked Valve Jira listing, October 2, 2013.
• Earlier mentions: None identified in this video.
• Verification: verified for the listing; needs follow-up for the development claim.

Minh Le says he saw Half-Life 3 concept art

• Description: On May 23, 2014, Counter-Strike co-creator Minh Le (transcribed “Minley”), then promoting Tactical Intervention, said on a Twitch stream that he had seen something that “looked kind of like the Half-Life universe” and that “they’re working on it,” specifying concept art for Half-Life 3. Tyler could not find the clip and quotes PC Gamer’s transcription.
• Confidence: Mixed — the quotes are secondhand; the original clip is missing.
• Category: Development state
• Source: PC Gamer transcription of Minh Le’s Twitch stream, May 23, 2014.
• Earlier mentions: None identified in this video.
• Verification: unverified — the original clip is unavailable.

Dog model leaks from the SteamVR Performance Test

• Description: Around August 2015, a Dog model leaked in jigsaw-like chunks on 4chan. Tyler says the model came from an early build of the SteamVR Performance Test, which was filled with development assets from other projects — chiefly Left 4 Dead 3 but also Half-Life 3 — including the Dog model and scripting files. Steam’s depot system allowed earlier versions of the software to be downloaded.
• Confidence: Fact — datamined assets from a public Valve build.
• Category: Development state
• Source: Datamine of an early SteamVR Performance Test build.
• Earlier mentions: None identified in this video.
• Verification: verified.

The HL3TXT leak from Dota 2

• Description: A few months after the Dog leak, an update to Dota 2 shipped plain-text files — effectively Source 2’s equivalent of FGDs — defining entities, NPC AI behavior, quests, and procedural generation. Tyler says these were from the canceled 2015 Half-Life 3 and were reportedly leaked so Valve could gather feedback on ideas after roughly two and a half years of development.
• Confidence: Mixed — the files are documented; the motive and project attribution are reported or asserted.
• Category: Development state
• Source: Dota 2 update datamine (hl3.txt files), late 2015.
• Earlier mentions: Explicitly links the files to the 2013 FGD leak covered earlier in this video.
• Verification: verified for the files; needs follow-up for the leak motive.

The Lab release and cut content that became Half-Life: Alyx

• Description: The Lab released on May 4, 2016 with Half-Life music on its loading screen. Tyler says a cut element from The Lab became Half-Life: Alyx.
• Confidence: Mixed — the release and music are fact; the cut-content claim is Tyler’s.
• Category: Development state
• Source: The Lab (2016); Tyler’s analysis.
• Earlier mentions: None identified in this video.
• Verification: verified for the release and music; needs follow-up for the cut-content claim.

The Sephilon correspondence and “posthuman” art

• Description: Tyler says he corresponded with someone calling himself “Sephilon” who claimed to be a Valve employee and supplied information and “posthuman” art. Tyler leaves open whether this was a genuine whistleblower.
• Confidence: Unclear — the correspondence occurred, but the source’s identity and access are unresolved.
• Category: Development state
• Source: Tyler’s private correspondence with “Sephilon.”
• Earlier mentions: None identified in this video.
• Verification: unverified — no independent confirmation of Sephilon.

Game Informer claims earlier Half-Life 3 RPG and FMV iterations

• Description: On January 17, 2017, Game Informer published an article claiming its sources had described earlier Half-Life 3 iterations, including an RPG and a full-motion-video game. Tyler notes none of these claims has been confirmed in the eight years since.
• Confidence: Unclear — anonymous sourcing, never corroborated.
• Category: Development state
• Source: Game Informer article, January 17, 2017.
• Earlier mentions: None identified in this video.
• Verification: unverified.

Valve press roundtable: the “VR3” icon

• Description: At Valve’s first press roundtable on February 13, 2017, Tyler asked about a “VR3” icon bearing the Half-Life logo visible in a screenshot of someone playtesting The Lab. He identifies it as an early Half-Life: Alyx build. Gabe Newell deflected, saying some “childish” employees wear Half-Life 3 t-shirts to GDC.
• Confidence: Mixed — the screenshot and quote are documented; the VR3/Alyx identification is inference.
• Category: Development state
• Source: Valve press roundtable, February 13, 2017; Tyler’s firsthand question.
• Earlier mentions: None identified in this video.
• Verification: needs follow-up — Valve confirmation that VR3 referred to Alyx.

Map repository leak includes Episode Three, Half-Life 3, and an Alyx/Dog spin-off

• Description: On March 23, 2017, a user leaked all maps then on Valve’s developer repository for Half-Life 2: Episode One and Episode Two. Community analysis later identified files from Episode Three, Half-Life 3, and an unreleased Alyx-and-Dog spin-off called Gathering Resources.
• Confidence: Mixed — the leak is documented; the project attributions are community analysis.
• Category: Development state
• Source: Leaked Valve developer map repository, March 23, 2017; community analysis.
• Earlier mentions: None identified in this video.
• Verification: verified for the leak; needs follow-up for the attributions.

Epistle 3

• Description: On August 24, 2017, Valve writer Marc Laidlaw published “Epistle 3,” an Episode Three story outline. Laidlaw answered questions on Twitter afterward. Tyler recounts the publication and the ensuing discussion without treating the outline as the shipped plot.
• Confidence: Fact — the blog post is a primary document.
• Category: Lore
• Source: Marc Laidlaw’s “Epistle 3” blog post, August 24, 2017.
• Earlier mentions: None identified in this video.
• Verification: verified.

Mike Shapiro teases a “certain Valve title”

• Description: On February 22, 2020, Mike Shapiro, the voice of Barney and the G-Man, appeared on Boundary Break and said at the end that he was “pretty excited about a certain Valve title releasing very soon.” He added that later in 2020 there was “a different big surprise coming” and to “stay tuned for that blast from the past.” Tyler says it remains unclear what this referred to.
• Confidence: Mixed — the quotes are on record; their meaning is unresolved.
• Category: Development state
• Source: Boundary Break episode featuring Mike Shapiro, February 22, 2020.
• Earlier mentions: None identified in this video.
• Verification: verified for the quotes; needs follow-up for the referent.

Half-Life: Alyx datamine matches the HL3TXT leak

• Description: Half-Life: Alyx released on March 23, 2020. Datamining found content from the canceled Half-Life 3, including spy grenades and zip lines, matching items outlined in the 2015 HL3TXT leak.
• Confidence: Fact — datamine of the shipped game.
• Category: Development state
• Source: Half-Life: Alyx datamine, March 2020.
• Earlier mentions: References the HL3TXT leak covered earlier in this video; Alyx’s files are presented as corroboration.
• Verification: verified.

Dario Casali on Source 2 and Half-Life development

• Description: In a post-Alyx IGN interview, Valve level designer Dario Casali said Valve’s lesson from Half-Life 2 was to “get some stable technology and then build a game on top of it,” and that Valve did not want to repeat the mistake of developing Source 2 and the next Half-Life game at the same time.
• Confidence: Fact — on-record interview.
• Category: Development state
• Source: IGN interview with Dario Casali, 2020.
• Earlier mentions: None identified in this video.
• Verification: verified.

Robin Walker on another 13-year wait

• Description: In a Polygon interview published the same day, Robin Walker said Valve still had “a lot of affection for the universe,” hoped to make more Half-Life, and did not think there would be “another 13-year wait,” adding that if there were, he would probably be too old to work on it.
• Confidence: Fact — published interview.
• Category: Development state
• Source: Polygon interview with Robin Walker, 2020.
• Earlier mentions: None identified in this video.
• Verification: verified.

The Final Hours confirms a 2015 Half-Life 3

• Description: Geoff Keighley’s The Final Hours of Half-Life: Alyx, released July 9, 2020, confirmed that a Half-Life 3 was in production around 2015 and that Episode Three’s production ended around the time Left 4 Dead shipped. Tyler says the team was excited and that things had started moving.
• Confidence: Fact — book reporting Valve’s account.
• Category: Development state
• Source: The Final Hours of Half-Life: Alyx, July 9, 2020.
• Earlier mentions: None identified in this video.
• Verification: verified.

HLX appears in Dota 2 demo-file parameters

• Description: In a March 21, 2021 Dota 2 update, the prototype codename “HLX” began appearing in demo-file parameters, almost a year to the day after Alyx’s release. Tyler treats this as the approximate start of the project, built on engine work begun for Half-Life: Alyx.
• Confidence: Mixed — the string is a datamined artifact; the start-date inference is Tyler’s.
• Category: Development state
• Source: Dota 2 update datamine, March 21, 2021.
• Earlier mentions: Builds on the Half-Life: Alyx engine work discussed earlier in this video.
• Verification: verified for the string; needs follow-up for the project start date.

Community attempt to reverse-engineer Half-Life 3

• Description: In September 2021, community members attempted to reconstruct Half-Life 3 from compiled code in public Valve builds of Half-Life: Alyx, Dota 2, and Underlords. The attempt was promising but unfinished; Tyler says it clarified what the 2015 Source 2 Half-Life 3 was meant to look like mechanically.
• Confidence: Mixed — the project is documented; the conclusions are community inference.
• Category: Technology
• Source: Community reverse-engineering project, September 2021; Tyler’s account.
• Earlier mentions: References the 2015 Source 2 build and HL3TXT leak covered earlier in this video.
• Verification: needs follow-up — published findings or results.

Famitsu: Greg Coomer says Alyx signals more Half-Life

• Description: On August 8, 2022, as the Steam Deck launched in Asian markets, Famitsu published an interview with Steam Deck developers. Greg Coomer (transcribed “Greg Kumer”) said Half-Life: Alyx was “a sign that Valve has more to say about that world” and that Valve loves the Half-Life universe.
• Confidence: Fact — published interview.
• Category: Development state
• Source: Famitsu interview, August 8, 2022.
• Earlier mentions: None identified in this video.
• Verification: verified.

Collector shows Episode Three and Half-Life 3 art prints

• Description: On August 28, 2022, collector David McGravy (as transcribed) showed dozens of art prints he had obtained from a Valve contact during the company’s 2017 office move. Some depicted Episode Three, Half-Life 3, and the canceled Alyx-and-Dog game whose elements evolved into Half-Life: Alyx.
• Confidence: Mixed — the prints exist; their project attributions are Tyler’s and the collector’s.
• Category: Development state
• Source: David McGravy’s collection, August 28, 2022.
• Earlier mentions: None identified in this video.
• Verification: needs follow-up — independent authentication of the prints’ origins.

Marc Laidlaw calls Epistle 3’s release “deranged”

• Description: In a March 1, 2023 Rock Paper Shotgun interview, Marc Laidlaw called his release of Epistle 3 “deranged,” said he was isolated and had nobody to talk him out of it, and said it created the false impression that Episode Three would have resembled his outline: “all the real story development can only happen in the crucible of developing the game.”
• Confidence: Fact — on-record interview.
• Category: Lore
• Source: Rock Paper Shotgun interview with Marc Laidlaw, March 1, 2023.
• Earlier mentions: Revisits Epistle 3 from 2017, covered earlier in this video; Laidlaw now says the outline was not representative of Episode Three.
• Verification: verified.

Deadlock closed-alpha datamine

• Description: Deadlock entered closed alpha in April 2024. As access widened, datamines found Half-Life-adjacent assets including the Xen Gorilla, Xen Jellyfish, and Xen Swooper (all transcribed “Zen”), the Feral Manhack, the Pentatank, and Off-World Workers and Off-World Stors. Tyler says this is where Half-Life 3 interest begins again, without claiming the assets are confirmed HL3 content.
• Confidence: Mixed — the assets are datamined; their connection to a Half-Life 3 project is inference.
• Category: Development state
• Source: Deadlock closed-alpha datamine, April 2024.
• Earlier mentions: None identified in this video.
• Verification: verified for the assets; needs follow-up for their project.

Half-Life 2’s 20th anniversary and the Noclip documentary

• Description: On November 15, 2024, Valve released a major Half-Life 2 20th-anniversary update and commissioned Danny O’Dwyer’s Noclip documentary. Tyler says Valve was open about where Episode Three went and hinted at the future; the documentary includes statements about innovation enabling gameplay innovation and Valve being “really excited to keep going there.”
• Confidence: Fact — official update and documentary.
• Category: Development state
• Source: Half-Life 2 20th-anniversary update; Noclip documentary, November 15, 2024.
• Earlier mentions: None identified in this video.
• Verification: verified.

New or changed in this video

• The video is mostly a recap: it synthesizes roughly 25 years of public statements, magazine coverage, leaks, and datamines, and debuts no new primary document.
• Tyler states explicitly that Episode Three had already been shelved by mid-2009, using the G4 and Steamcast interviews as the pivot.
• He disputes Valve’s 2010 characterization of the weaponizer and identifies it as an Episode Three weapon visible in Noclip’s documentary footage.
• He says Episode Three snow textures were long known but only recently recognized as Episode Three assets.
• He links the 43-member “Half-Life 3” Jira group from June 2013 to the procedural-generation project described in The Final Hours of Half-Life: Alyx.
• He dates the HLX prototype’s start to the March 21, 2021 Dota 2 update, almost a year after Alyx.
• He presents Half-Life: Alyx’s spy grenades and zip lines as corroboration of the 2015 HL3TXT leak.
• He lists 2024 Deadlock datamine entities as renewing Half-Life 3 speculation but does not claim they are confirmed HL3 content.
• The closing minutes reuse a clip from Tyler’s earlier Episode Three video, which predicted the episodic model would become a larger Half-Life 3.

Notable quotes

• “Is it possible that Half-Life 3 is soon to follow from the proverbial back burner? No.” — Gabe Newell, June 13, 2003.
• “EP3 is sort of … a victim of our willingness to experiment.” — Gabe Newell, Steamcast, August 12, 2009.
• “That was the last time Valve ever said the name Episode 3 publicly.” — Tyler, on the March 2010 Edge retrospective.
• “The episodic model failed.” — Gabe Newell, Develop, May 9, 2011.
• “What people got wasn’t episode 3 at all.” — Marc Laidlaw, Rock Paper Shotgun, March 1, 2023.
• “I don’t think there’s going to be another 13-year wait.” — Robin Walker, Polygon, 2020.

Open questions

• Where did the 2013 FGD files for Episode Three and Stars of Blood come from?
• Was “Sephilon” a genuine Valve source, and what was the “posthuman” art?
• Is HLX the same project as the 2015 Source 2 Half-Life 3, and what is its current status?
• Which Deadlock assets, if any, are actually Half-Life 3 content?
• What was the Stars of Blood project?
• What did Mike Shapiro’s February 2020 “certain Valve title” tease refer to?
• Why did Valve describe the weaponizer as unrelated to Episode Three in 2010?
• What was the exact date and context of the blue-crowbar forum post?