Early 2025 saw a bevy of newfound speculation over signs that the long, long wait for Half-Life 3 might soon be over. Now, data contained in some new Valve game updates suggests that the project known in Valve engine code as “HLX”—and widely assumed to be Half-Life 3—might be reaching the final stages of production.
In a new video, longtime Valve watcher Tyler McVicker goes into detail on a bevy of new variables and strings found after spending hours datamining the latest update to Dota 2 (the first update for that game since mid-December). The strings suggest a wave of behind-the-scenes Source engine changes dealing with the kind of “optimization and polish” that “happen[s] at the end of a game’s production cycle,” McVicker says. “This is getting to the point where it does feel as if Valve is nearing completion of the production of HLX.”
Those changes include a set of new code in a file called AI_baseNPC.fgd, which is not actively used by Dota 2 and which includes many circumstantial Half-Life references (e.g. “machinery,” “alien blood”). The specific code in this latest update deals with letting the engine scale the level of an NPC’s AI simulation based on its distance from the player, a refinement that McVicker says is “absolutely… optimization work” and an apparent sign that “Valve has hit the optimization and polish phase” on HLX.
McVicker also makes note of a February 25 update to Deadlock which includes a new variable suggestively named “hlx_fsr3_min_reactiveness.” That’s being taken as an apparent sign that AMD’s AI-powered FidelityFX Super Resolution upscaling is in use in a current HLX development build, which would be another sign that HLX “legitimately is nearing the end of development,” as McVicker puts it. “You don’t use FSR until you’re nearly done with a game. Those AI post-processing systems are not supposed to be used for development.”
Don’t you dare give me hope
The newly discovered engine updates are a particularly good sign for the HLX project after credible reports that the game had gone into a friends and family playtesting phase at Valve near the end of 2024. While many Valve projects have seen major changes after that kind of testing, McVicker says that these new engine updates are “confirmation indeed that HLX survived the holiday break, does not seem to be going through any form of reboot, and [that] an announcement seems to be inching ever closer.”
While McVicker doesn’t go into detail on every single engine variable hinted at in the latest Valve game updates, he provides a summary version with informed speculation on what all those variables could mean for HLX. That includes signs of a “heavily evolved” physics engine from Half-Life 2 that can seemingly track object traits such as buoyancy, flammability, deformation, as well as fluid simulation and dynamic sound properties based on an object’s status.
Most intriguingly, McVicker talks up signs that HLX may include a new NPC “mood system,” letting these AI-controlled characters react “verbally and non-verbally” to what they can see, hear, or even smell in the immediate area. The code also hints at “dynamically adjustable nav meshes” that will let NPCs navigate easily around destructible environmental hazards, and at a system for in-game objects to be placed semi-randomly during multiple playthroughs, a la Left 4 Dead‘s director system.
We know it’s easy to be skeptical after so many years of fruitless speculation regarding Half-Life 3. But when McVicker says that signs suggest that an actual Half-Life 3 announcement could come this year, let’s just say we want to believe.