New Half Life 2 campaign on Steam: Prospekt. Fan-made but approved. Available 11 Feb.

[Heptagon_ru]

A 13-level campaign, approx as long as Episode One, developed by one fan developer. Approved by Valve and passed by Greenlight.
A sequel of Opposing Force, taking place in Nova Prospekt.
http://www.geek.com/games/prospekt-new-half-life-2-campaign-launches-february-11-on-steam-1644860/
http://steamcommunity.com/games/399120/announcements/

But seems a bit secondary to me, and also like a forced marketing.

[InsaneJ]

Marketing for what? Half-Life 3? Like that's ever going to happen in our life times :)

There are several other free campaigns available for Half Life 2 made by the community. This one is only different because it's paid content. It's made by 1 person who spend a ton of time on it and from the looks of things he did a good job.

The question a lot of people will be asking is if 13 levels for a pretty much ancient game are worth 9 Euro. That's as much as the entire game of Half-Life 2 costs. I'll probably get it somewhere down the line, but in a sale for maybe 2 or 3 Euro. Time to hit that Add to wishlist button :)

[Heptagon_ru]

Forced marketing for itself. I mean the same what you said better: there are many other good free mod campaigns for HL2, and this one doesn't look much better than them, but is kinda artificially promoted, with all that Valve approval, strong words like "sequel" and stuff.
The levels from the trailer looks too familiar, almost as playing old levels with a new Shepherd character, which is the same as playing them as Gordon.
And totally agree with the price thing.