

"The other thing you can do is if you press TAB it will give you a split screen, so that you can see what your co-op friend is looking through. "We've also added a way for you to mark up in context in the world, so if I'm playing with you and I want you to put a portal here, I can choose it and then you'll see, you know: 'Hey, my buddy wants a portal here.' Also, a player can shoot a portal onto their friend's portal and take it over - which kind of comes into play. "Each player can go through each others' portals in any way. "There's four different colours - we're actually testing right now to figure out the other two. "You don't play as Chell in co-op, you play as these two little robots because you're going to get cut in half by lasers and crushed by crushers - and robots are a little more appropriate for that. Fictionally, it kind of fits inside of the single-player game but there are custom levels that tend to be pretty complicated. "We're going to have two-player co-op, so you can play with a buddy," explained Johnson.

As you might expect, each player will be given a specific colour for their personal portal - while co-op levels will be separate and "pretty complicated".
