It seems an ex-Valve writer has written up a blog post detailing what could have been the story for Half-Life 2: Episode 3. The writer, Marc Laidlaw, joined Valve in 1997 where he helped write and design Half-Life, Half-Life 2 and the episodes that continue after.
The blog post can be found here, but the site has been annihilated by eager fans wanting a read, so see this archived link.
The actual post doesn't name Half-Life directly, but the title is "Epistle 3" and it features characters such as "Gertie Fremont", so it's quite obvious really. It's worth noting though that Marc tweeted this out:
My website's down for now. I guess fanfic is popular, even a genderswapped snapshot of a dream I had many years ago.
— Marc Laidlaw (@marc_laidlaw) August 25, 2017
So this could be something he had written quite a while ago and he's simply adjusted a few things. It's sad really, as it's likely we will never get to see an Episode 3.
I have still yet to finish Episode 2, but I've also come to appreciate the story.
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