
Several months ago, Source 2 references were spotted inside the Source Filmmaker code. Now, it’s the turn of Half Life 3 to appear with new scripting fragments added as of January 2014.
You can think of them as placeholder text more than anything else and point to file locations that just might exist in Valve’s render farms. While it’s not the best possible explanation that Half Life 3 is in development, and it does nothing on its own, it at least points to a possible connection between Source Filmmaker and Half Life 3 in some way.

If Half-Life 3 ever happens, what big innovation would justify it in Gabe Newell's eyes?
Just go back to what made Half-Life 2 special: the physics.
At the time, it was groundbreaking and arguably influenced a wave of other games that started to experiment with more interactive and dynamic environments. For a while, physics-based gameplay became a trend. But if you've played any first-person shooters in the last decade, you've probably noticed that most developers have either abandoned those ideas entirely or significantly toned them down. The focus shifted away from immersive world interaction toward faster pacing, scripted set pieces, and visual spectacle.
And while you're at it, ship it with a robust modding tool. That’s another thing most developers have completely given up on. It could offer a much-needed alternative to the current AAA landscape, which feels increasingly trapped in a cycle of cinematic universes and safe, homogenized content. In a world of "Marvelized" blockbusters, a game that draws inspiration from the experimental spirit of the late 1990 and mid-2000s wouldn’t just be nostalgic,it would be genuinely fresh. Ironically, looking back might be the most forward-thinking move a studio could make right now.
Here's something innovative, finish the God damn story. Wow, a concept! Locking a series behind forced innovation is stupid, and stupidity is not innovation.
1. Dynamic AI for NPC - Supporting character AI that responds to your voice in real-time. Imagine getting pinned down and then just say "Alyx, throw a smoke grenade and give me covering fire!" and then she does it after responding "OK!". How about having a conversation with Alyx?
2. FOV graphical render using NVMe SSD - A graphics rendering feature that is built-in the game engine so that your GPU and CPU only renders what player is seeing. Current graphics engine renders the world beyond the FOV because of hardware limitations in immediate rendering as you pan your camera/view. Having a graphics rendering system that renders graphics instantly and only what you're seeing allows for richer, more detailed worlds or less RAM usage.

The project codenamed HLX, which is thought to be Half-Life 3, is reportedly being widely playtested ahead of a Summer reveal and Winter release.
I wonder if the rumours are true - that it has a highly destructible environment and very reactive with hot/cold with realism placed on wind and other physics, I guess it makes sense, HL2 was very impressive at the time and it carried over into GMOD. That's what I really liked about it, everything built into the engine.
The only thing that might slightly disappoint me is if they don't upgrade the graphics more. I like that Source and Source 2 has such a clean look, I just hope they push it so it's more like Source 2.5 if they haven't budged it up to Source 3. Being (supposedly) the game to finish the original story I hope they go all out if they can while maintaining high frame rates with modern hardware.
It just seems so impossible that after so many years and so many false leaks and rumours this might be it.
I don't know how to feel about this the game has so much weight on it in terms of expectations now half life alyx was amazing so I think they can do it but they would be feeling the pressure

If Half-Life ends with 3, it should be a call for more series to wrap it up.
Half Life 3 finally tease (^-^) (howahhhh)
Sadly it's just another fluke...
Half-Life 3 coming in 2038!
I honestly think Valve is scared to make this game, with the amount of hype it would have to live up to.
Can we stop reaching so hard for HL3 and either wait for announcement or move on? At this point HL3 stuff is nothing more than click bait attempts.