Yesterday, we announced that Steam and all our Source engine games will be coming to the Mac. Sound too good to be true? Well, guess what: It is true! There are no catches! Sometimes life actually works like that. The bad news is that we've just truth bombed your hard-earned lie detector back to the stone age, and you'll probably lose all your money to the next international lottery scam that sneaks through your spam filter. Still, Steam on the Mac!

We like the platform wars in the forums so much that we've decided to add a new platform to the fray. Later this spring, we'll be releasing both Left 4 Dead 1 and 2 on the OSX operating system for Mac computers, all through Steam.

We're plugging away at the Engineer update. He's an interesting class to work on, because he creates a larger footprint in the game than any other class. This means we have a lot of options to work with, and the resulting set of ideas is truly daunting. Since we've already built and playtested some things that haven't worked out (with no false modesty, I think we've mastered the art of rapidly making things that aren't fun), we thought it might be interesting to give you some of our failed experiments.

In the first two months of Left 4 Dead 2's release, 28,981,249,043 zombies have been shot, bludgeoned, chainsawed and killed — or, for our younger readers, taken to a farm where they can frolic and shuffle around forever.

You read that correctly: 28 BILLION. To put that number in perspective:

As the Administrator mentioned last week, we've sorted through the 11,000 submissions to the Propaganda contest and picked some of our favorites from the frankly jaw-dropping number of first-rate entries. Scroll and enjoy!

Firstly, as should come as no surprise to anyone, it is my sad duty to reprimand the various con artists and charlatans in our community who insist on making a mockery of the hard work of others by cheating to win. The following is a list of the top twenty kill counts of the recent Demo/Soldier competition:

In the latest update, we've finally fixed the Double Crouch Jump bug—a longstanding issue involving Scout not being able to double crouch jump without looking like his legs are made of raw bacon strips held up in a wind tunnel:

With our last update having come out a few weeks ago and the next one a few weeks out, we wanted to let people know what we are working on. In addition to "The Passing" DLC, we are working on some other updates coming for both PC and 360. While not a complete list by any means, we wanted to give a heads up on a few Versus changes coming.

Today we're unveiling the TF2 Contribution site. This nifty site will allow anyone who's made a custom piece of TF2 content to submit it to us, with a view to it appearing in-game. Many of you have been building fantastic TF2 work for a while now, and we wanted a way for you to get it in front of all TF2 players, and for everyone to see that you were the one that built it.

For this weekend only, Microsoft is hosting a free multiplayer weekend for Left 4 Dead 2. What does this mean? You don't need to have an Xbox Live Gold account to access Left 4 Dead 2's multiplayer features. That's right: You will be upgraded from Silver to Gold for free. You can go online alone or with a split-screen friend. This event starts at 5pm GMT Friday, January 15th and ends at 5pm on Sunday the 18th.

We are releasing the Left 4 Dead 2 Authoring Tools and Left 4 Dead 2 Add-on Support today.

PLAYERS: If you are not looking to design but play custom campaigns all you need to do is install the add-on support package. Just go into steam and open up the Tools tab. Look for the entry labeled Left 4 Dead 2 - Add-on Support click and install it. This download is sizable, but will update your L4D2 installation to allow running ANY map, including custom maps made for the original Left 4 Dead. Once installed, you do not need to run this application, it will always be active.

We will be updating the Left 4 Dead 2 game UI to include links to this package when applicable but for now please just download it directly. If you see any missing textures or models from your favorite map let us know in the forums.

DESIGNERS: Besides also downloading the above file you will need to download the Left 4 Dead 2 - Authoring Tools. Downloading it will add applications, utilities, and example files that are useful for building L4D2 game add-ons. These are similar to the tools released for Left 4 Dead, but include many updates and new features. Among the most useful are:

Gamemode Logic: Designers can now make a single map that can behave differently depending on the gamemode in which it is being played. This can dramatically reduce the file size of Campaign add-ons, as the same map can be used for Co-op, Versus, Scavenge, and Survival.

Director Logic: Maps can now alter their layout and behavior depending on how "angry" the A.I. director is. The better the Survivors are doing, the angrier the AI Director seems to get. This allows you to base variable paths and other events on the player's skill and current conditions.

Scavenge Mode Support! All the elements map authors need to support Scavenge in their maps. This includes game props as well as a full example in the form of Deadline 2, an updated tutorial campaign.

We have included an updated tutorial to help you get going and as always you can join the discussion on the map designer email list. What we want for New Years is to get to play your custom maps in Left 4 Dead 2.

For the best user experience and to take advantage of the new map and nav mesh formats, Left 4 Dead 1 Map Makers will want to compile Left 4 Dead 2 specific versions of their map in the new tool.

Happy Holidays,

The Left 4 Dead 2 Team

With the success of the AI systems of Left 4 Dead, we've been continuing to develop these technologies to create new kinds of game experiences. Team Fortress 2 is an excellent "sandbox" for explorations of this sort, and we've been quietly doing so for much of this last year. Some of the results of these explorations are TF "bots" — AI-driven player proxies with simulated humanlike senses, reaction times, and tactics. Although the TFBots are not yet complete, they play a pretty decent game of King of the Hill.

We thought you might enjoy testing your skill against these work-in-progress digital killing machines.

We've got one more update to go out to our backend item system. After that, we'll be granting all the missing items that weren't granted properly when you finished achievements.

...the Soldier!

Victory on the Internet Day has been declared! The war is over! Who won? We don't know! Yet!

Luckily, I, Robin Walker, was up all night building a kill-calculating machine for just such an eventuality. We turned it on, the building filled with smoke, and right now a fireman is yelling at me to leave the building with everyone else. I'll leave when they pry this tiny netbook out of my cold dead hands. Or when an angry fireman fireman-carries me out of the office, which is what is happening right now. Anyway, once all the firemen calm down, we'll announce the War results with today's huge update. To pass the time, go get yourself a fresh mouse and start reloading this page as fast as you possibly can.

You heard right As of noon PST today, the Demoman/Soldier WAR! is over. The score is, as of this writing:

Demoman Killed: 6,323,921

Dead Soldiers: 6,298,465

It all comes down to this. I'd give you a motivational speech right now, but the time you wasted reading it would be less time you spent making a difference on the battlefield. Go ahead and break the bad news to your grandfather: YOU are officially now the greatest generation.

Adding in the points awarded to our recent Propaganda Contest winners—60,000 frags added to the Killed Demomen score and 25,000 added to the Killed Soldier score—the war currently stands neck-and-neck at 5,727,928 Killed Soldiers to 5,742,720 Killed Demos. We need to stress to you that we have not gamed these numbers in any way: After a solid week of gut-grinding combat and an astonishing 11,470,648 total kills, the Demomen and Soldiers are separated by a mere 14,792 points.

Soldiers continue to hold the lead in the war—but like an M&M lodged up their collective noses, the Demoman refuses to melt away quietly. In other M&M-Stuck-Up-Drew-Wolf's-Nose metaphor news, the Soldier's lead remains thin as a candy coating. In fact, judging from our most recent numbers (4923531 Soldiers killed to 5056134 Demomen killed), the Demo actually seems to be closing the gap as the War hurtles to a close.

If there is a tragedy in war (besides all the killing), it is that there must be a loser. Currently, we all know who that loser is.