Steam Offers Alien Storm Game, Source for FREE

"a major publisher releasing a title under free-as-in-beer and free-as-in-speech terms IS political."

Eh, I think you're stretching things a bit.  It's being released through Valve, but at the same time, you could just as easily say that that it's just a free port of a previously free UT2k4 mod that was made by a cool indie team.  The only difference now is that the Black Cat folks have more prominent (and well deserved!) day jobs, and their employer's giving some free promotion to an impressive mod.

That being said, even as an off-topic post, I still find it more interesting that some of the other articles that get posted.  For example, the article about people in England needing to lock their doors doesn't really have a political hook (beyond involving crime prevention) and doesn't really have a gaming hook (beyond the fact that gaming consoles represent one of the many things that burglars like to steal).

As for Alien Swarm, I've only played the UT2k4 version, but it was a blast.  Most immediately noticeable is that it's using an FPS engine for a non-FPS view.  Instead, it's top-down view of a 3D world that plays like a 2D game.  W/A/S/D is used for absolute movement (i.e. W always moves to the top of the screen regardless of which way your character's facing), and your character always faces and fires toward your mouse pointer.

There are a number of things in the game that can also be seen in the L4D series: Friendly fire is always on (and really forces team-work; in a top-down setup, it's a lot easier to split up who's responsible for enemies coming from which direction).  Games consist of campaigns that're generally designed to be completed in a single extended play session with the campaigns broken into discrete levels (corresponding to the sections between safe houses in L4D).  Characters have limited carrying capacity and have to rely on being part of a team to get everything done, and bots are used to pad the team out to 4 players.  Supplies are finite but not anemic and are replenished between levels.  Characters all have pre-assigned names and personalities.

Unlike L4D, Alien Swarm has distinct character classes (heavy weapons, medic, tech, etc.).  It also has more complicated maps.  It's harder to get lost in a top-down view, and it didn't have the commercial necessity of trying to appeal to as wide an audience as possible, so they could make things a bit trickier.  In addition, the potential for characters with certain skills or equipment allowed them to vary some of the routes and interaction that could take place with the level.  Finally, it's got some RPG elements with characters leveling up skills between maps based largely on their performance in the level.

Overall, it was a fun game.  Unless they completely botched the Source port (which I find highly unlikely), I'd say it's worth the download.