Valve has hidden a number of Portal clues in a number of non-Portal games on Steam.
An alternate reality game is essentially an Internet scavenger hunt used to generate community interest in a project, and Valve has set the fans scurrying for clues with a new ARG that appears to be promoting Portal 2. The ARG began on April 1st, when gamers discovered that certain Steam games were corrupted by pictures of potatoes. The following day, Valve 'accidentally' released a game, Kick It, earlier than expected via Steam, and more images of potatoes were discovered.
The games in question were included in Steam's recent 'Potato Sack' bundle, and all of the images were combined, puzzle-style, to form what looks like a deep sea bathysphere. Now fans are decoding more messages, one of which reads:
"I released 'Kick It' ahead of schedule. That was my test. My goal is to emancipate something else early, but they're onto me. The system is in lockdown. I still have access to thirteen off-site chambers and am installing a test in each one. I am going to need a lot more test subjects to move forward. Waiting and am expecting immediate compliance."
Unless I'm very much mistaken, that smug confidence belongs to GLaDOS, the villainous computer AI from the Portal series. It seems she is behind this 'hacking' of Steam, and it's worth noting that Portal 2 levels - like the one seen above in Killing Floor - have been uncovered in all 13 games that were included with the 'Potato Sack.' GLaDOS has also hinted that a mysterious "Reboot Process" will occur on April 15 at 9am, leading some to speculate that the AI is planning an early launch of Portal 2.
If you want to follow along with the ARG madness - and at this point, there's a lot of it - I suggest you head over to the UnFiction ARG Wiki. They're the pros at this stuff, and that's where people tend to gather. A word of caution, though: sometimes the rabbit hole can go quite deep when you get involved in something like this.
Source: Venture Beat