UPDATE: It's over.

Only on Christmas: Just launch Steam, go to the store page and click on "Install Game" to claim it. You may need to install it to own it after Christmas.

When GOG's servers kept crashing because of giving 3 free Fallout games, reddit was basically like "Fuck that, these guys have a shitty site." When Steam gives a single free game and their servers crash, reddit says "Valve is LITERALLY the best company ever."

Reddit and their Steam fetish...

That said, I did pick it up, and would gladly play sometime with some GOGers in the future.

thats cause those bastards dont understand what is fallout, yea i got it too, zombie hunting any day

Free game is free. So yeah i picked this one up.
Should be fun adding more undead minions to my army.

Thank you, this is wonderful. Merry Christmas!

It's only multiplayer?

No, but you can definitely tell when playing that you're meant to play with friends.

actually, you have to install it to keep it beyond the offer

EDIT: I was mistaken; replaced original post to avoid confusing others.

yes, and as has been stated elsewhere it will vanish unless installed by the end of the offer.

i'll leave you to find that info yourself though

Actually, heres the info - I already had it prepared, but im not a ttotal shit:

"To claim your L4D2 gift, all you need to do is install it.

If you don’t install, it goes back to its regular price and you miss out! The zombie apocalypse is more fun with friends so make sure to tell all your mates to install it as well."
http://www.l4d.com/blog/

This was also dropped from the official steam fb page before being removed.

Oh, well that's confusing and lame; the other things I kept forever said Complimentary so I expected it worked the same way.

I can't sacrifice that many gigabytes at the moment so I guess I'll try partially downloading it in case that's sufficient.

precisely why i made made my intial comment then tried to find the link so that people in a situation such as yourself (as i am also in that boat) had that as a possible option / loophole, rather than planning on installing three days down the line and finding out its has vanished.
hopefully the collosal clusterfuck with the servers earlier (and the 1000s of comments obn their FB page alone - never mind the rest of the web) will force valve / steam into honouring all "redeems" from before the end of the offer, but I'll remain cynical on that.

I tried to install it but has been going at a speedy 22kbps over the past few hours.

...And I still won't bother getting it. :P

grabbing it is one thing, but having to install it to keep it?. come on.can't even get the store page up.