According to GLaDOS, Portal 2's dry-witted antagonist, scientific achievement is all about cooperation. That's why one of history's greatest scientific teams is the duo of "Albert Einstein and his cousin Terry." Of course, it's pretty obvious she's lying through her robot teeth on that one. But what would Portal be without a villain spouting out hilarious bits of grossly inaccurate misinformation at every turn? That's just Portal. But all this cooperation business? Well, that's certainly new.
Fortunately Valve is here at PAX 2010 to explain what co-op is all about, as this new feature was the focus of the developer's latest Portal 2 demo. To put it in context, this mode is one of the many new ways Portal 2 is expanding on its predecessor. In addition to a single-player story that Valve claims will last about twice as long as the first Portal, the co-op mode will clock in at roughly the same length--making for an overall package that's supposedly four times as large as the original Portal.
Co-op tells a parallel story to the single-player mode, with a pair of new robotic protagonists simply named Blue and Orange. They're an oddly cute pair, one squat and one oblong, looking almost like a robotic Bert and Ernie. The two players can interact with each other in a variety of ways that range from critical to solving puzzles all the way to almost entirely nonsensical. The latter includes the ability to wave at one another, or just simply start dancing in celebratory glee.
But as hard as it may be to hear, dancing alone won't solve puzzles. To solve puzzles, you'll need to master the new co-op mechanics. We were shown a few examples of ways the two players will have to interact with each other to progress through GLaDOS' increasingly devious death traps. One very basic option is a paint tool that lets one player tag a surface in order to indicate to his or her teammate that this is the place where you need to drop a portal. According to Valve, this is to alleviate the vague gesturing and eventual frustrated shouting that tends to creep up whenever two players are trying to tell each other where to go in an online game.
Beyond simply tagging walls and surfaces, you can now work together by combining your portals to send one player to areas he wouldn't normally be able to reach on his own. As one example, Valve showed us how infinite falling can work in a co-op scenario: Player B sets up two portals above each other and lets Player A fall infinitely between the two. Then, Player B carefully aims and shoots a portal onto a distant wall to launch Player A--with all that built-up momentum--across a pit of deadly goo and onto a safe ledge. There were times in the first game when you could do something like this, but infinite falling was almost always too disorienting to use strategically. But with a friend at your side, it's suddenly a mechanic that can be used quite a bit more often.
Adding more complexity are some of the new objects you can interact with in the world. One we were shown was a reflector cube designed to reflect the path of deadly lasers. These come in handy whenever the door leading to your goal is powered down, making it necessary to guide laser beams to laser receptacles to power the door back up. One player drops the cube in a certain location, while another drops portals around to carefully guide the laser beam along. The trick, of course, is making sure you don't accidentally zap your buddy with a deadly laser beam along the way.
Everything we were shown suggested a very promising follow-up to the original Portal. This new co-op mode is looking a bit more complex and heavy on mechanics, so it could very well provide a much steeper learning curve. But between GLaDOS' reliably laugh-worthy dialogue--and there was plenty of it--and the sense of accomplishment that goes along with solving those puzzles, we'll go ahead and assume that the steeper climb will be worth it. You can expect to see Portal 2 arrive on February 9.