Putting aside their usually persistent humour for a minute, Valve has sent through word the "Perpetual Testing Initiative" (or level editor DLC) for Portal 2 is now available for Mac and PC.

The "Perpetual Testing Initiative" allows players to easily create, share, and play Portal 2 puzzles. The Initiative comes with a simplified Puzzle Maker that allows that creation of mind-bending puzzles without ever leaving the game. The Puzzle Maker can directly publish maps to the Steam Workshop where users can browse, vote on, and select to play them. Selected puzzles will automatically be downloaded and installed inside Portal 2.

You can learn more by clicking here, otherwise be sure to drop us a line if you do make some of your own puzzles in the Comments section.

One of the stand-out features for Portal 2 wasn't the game's mechanics, setting or puzzles. It was the tight, comedic scripting and its delivery. Few games have managed to reach humour heights like those found in Portal 2 and we're happy to report this benchmark remains in the recently announced Portal 2 DLC "Perpetual Testing Intuitive". Or at least as the new trailer for it would have us believe.

There's no real gameplay shown here, but the point of this new content is to offer up an easy-to-use level creation kit so everyone can get in and have a crack at making something that's easily shareable and easy to use.

Watch the new trailer for the forthcoming DLC (May 8) below, or click here for a direct link.

Valve have announced upcoming DLC for their acclaimed first-person puzzler Portal 2 will launch on May 8th 2012 and will include a basic map maker and the ability for players to publish and share their creations on Steam Workshop.

The "Perpetual Testing Initiative" allows players to easily create, share, and play Portal 2 puzzles. The Initiative comes with a simplified puzzle maker that allows that creation of mind-bending puzzles without ever leaving the game.

The puzzle maker can directly publish maps to the Steam Workshop where users can browse, vote on, and select to play them. Selected puzzles will automatically be downloaded and installed inside Portal 2.

Unfortunately we don't have any more information than that -- no pretty screenshots or trailers to look at -- so keep an eye on Steam come May 8th.

In a move that will make many people happy, Valve have announced some free add-ons to Portal 2, due to land October 4th:

In "Peer Review", you and a friend will continue the story of loyal bots P-Body and Atlas as you puzzle your way through a mysterious new co-op test track and once again match wits with GLaDOS. The DLC also features a single player and co-op Challenge Mode, and leaderboards to compare Challenge Mode scores with friends and the Portal community.

To "hold you over" until the release, they've also released Volume 3 of the soundtrack, which you can download now, locally from AusGamers.

Eurogamer (by way of Gamasutra) has pointed out that in a recent interview discussing all things Dota 2 and Valve, Gabe Newell explained that Portal 2 was more successful on PC than console, while Left 4 Dead 2, surprisingly, was the reverse.

"We can never predict; I mean we just try to build good games and then we tend to be surprised," he told Gamasutra. "Portal 2 did better on the PC than it did on the consoles; Left 4 Dead did better on the consoles than it did on the PC.

"So you know we don't try to guess, because we're not sure what value there is to guessing," he added.

Valve have sent through word they'll be running a music video contest for Portal 2 where budding young creative types are charged with creating a music video for the end credits track from Portal 2, "Exile Vilify", by The National.

Starting today and running until midnight July 15th, the contest asks the community to make a music video for the song "Exile Vilify" using whatever visuals they choose. Once aspiring video directors have completed their work, they may submit their videos on YouTube using the tag PORTAL2NATIONALEXILE. After the deadline, Valve, The National, and the community will select the winner who will win a prize package including a guitar autographed by The National plus a collection of Portal 2 merchandise.

Obviously "using whatever visuals they choose" is an option to be taken in reason, and this is YouTube we're talking about, but it's also the internet. If you decide to enter, be sure to also share your video with us in the Comments section or on our Forums.

Valve have released Volume 1 of the soundtrack from Portal 2 as a free download, further cementing their awesomeness:

Whether you're a mega-science corporation with decades of test experience, or a young start-up liberating your first test subject from non-testing with a chloroform-soaked rag, Aperture guarantees results. Wake up your test subject, open the chamber door, and press play--let Aperture's patent-pending rhythmic compliance enhancers do the rest.

In addition there's a bunch of ringtones available from the official site, if that's how you roll, but otherwise you can just download the soundtrack in its entirety now locally from AusGamers.

Valve have let us know that the they have released a new downloadable book on Steam that recounts the behind the scenes developement process of the hugely popular Portal 2. Titled The Final Hours, the book can be purchased and downloaded from Steam for USD$1.99.

Journalist Geoff Keighley was granted unprecedented “fly on the wall” access to Valve to create this staggering 15,000 word multimedia experience. From the hush-hush Portal prequel that was shelved to the last minute scramble to complete the game’s story, The Final Hours of Portal 2 is a gripping and dramatic story brought to life by exclusive photos, videos, interviews, interactive experiences, and other surprises.

Portal 2 shipped on April 21st for PC/Mac, PlayStation 3 and Xbox 360. For more details on the game itself, swing by our in-depth review (AusGamers 9.8/10).

Last week we mentioned Valve's Doug Lombardi said in an interview that the first batch of downloadable content (DLC) for Portal 2 was potentially coming just in time for winter here in Australia, and over the weekend this was officially confirmed by the developer.

Portal 2 DLC #1 will offer new test chambers for players, leaderboards, challenge mode for single and multiplayer modes, and more.

Many of you speculated that because said DLC was coming from Valve, it would most likely be free, which they happily confirmed for you, stating that it would be free of charge across PC, PS3, Xbox 360 and Mac.

Now if only other developers/publishers would follow suit.

Using our powers of the understanding of what is north and south, we've deduced that comments made by Valve's Doug Lombardi saying that Portal 2 DLC would arrive in the US "this summer", it looks like we'll see it this winter (lucky y'all have us to work that out for you).

"We will be announcing some DLC for it, so folks can keep a look out for more content coming this summer," Lombardi said in an interview with Fast Company. "We'll be putting more details out about that in a week or so. We'll support that with more videos or more comics."

Hopefully we'll get a more complex expansion on the tools introduced throughout the campaign to really rattle the cortex. Stay tuned for more info as we have it.