When former Valve writer Marc Laidlaw released his synopsis for the rest of the unfinished series' plot last August, Half-Life fans were given a glimpse at something they'd been waiting years for: Closure.
Reading a plot summary is a long way from actually playing through Half-Life 2's final act, of course, but it's better than nothing, and nothing is all we've had since October 2007.
Some fans are now trying to turn it into something more. Project Borealis is an attempt to take what little we know about Half-Life 2: Episode 3 and turn it into a playable game, with an international team of modders now at work building the episode in the Unreal Engine.
It's still very early days - aren't they always, with these kind of things? - and like most fan projects, it may end up as unreleased as the actual Episode 3. But then, we've been down this road before with a Half-Life fan project and it actually turned out OK, so who knows.
In terms of what's been accomplished so far, here's the first in-engine footage:
And here's some concept art for Alyx's winter look: