Puzzle games shouldn't be anticipated like this. We shouldn't be so keenly looking forward to having our spatial awareness tweaked and fingered into a purple, bruised pulp.
Love Portal 2? Then don't forget to visit Games Radar's special Portal 2 launch centre, for all the latest news, movies, screens and action from the game.
The original Portal was included as a bite-sized treat inside The Orange Box; a treat that said, "Yes, we know you bought me for Half-Life 2, its episodes, and Team Fortress, but look at the clever stuff we're doing with our tech."
So, Portal 2 is a brilliant anomaly: a proper, full-length sequel to what was little more than a teaser, a bonus game. Portal's (and Portal 2's) heroine Chell's voicelessness and boiler suit make her virtually genderless.
Yet her AI challenger GlaDOS - the opposite of Chell's silent struggle to survive - is an AI consumed by the noisy, neurotic struggle to kill. It's all about Aperture Science - built on the comical conceit that science can only learn from the fatal mistakes of its subjects.
COLOR ME BLIND
Portal 2's solo story is a still-secret new chapter in the saga of Chell and GlaDOS, but we do get our hands on the opening levels of the completely distinct co-op campaign.
Meet Orange and Blue. Their relationship as a couple of constantly killed and instantly respawned buddies makes them a comedy team where you have some control over the jokes.
In the single-player you're confined to solving puzzles, and triggering the next funny response from GlaDOS.
As Orange and Blue, you can mess around with each other - drop a portal under your friend's feet, slamming him into a pool of acid; shear her in half with a thermal discouragement beam... you'll be helplessly tempted to do it all before you get around to solving the real problem.
The first level is a simple cube-passing problem, reminding you of Portal's basics. Robots can pass through the translucent blue veils, but those important switch-triggering cubes can't - meaning you'll need to pass it through the gaps in the wall to move along.
It's not hard, but it gives you a chance to reacquaint yourself with the controls. Both robots have control over a distinct pair of portals. Orange has red and yellow, and blue has purple and cyan.
To keep things simple, you can't leap from one pair of portals to another - red leaps only to yellow. And Orange can't fire purple or cyan portals, as many people were trying to do. If they could, it wouldn't really require co-operation.
The next puzzle involves one robot setting up an infinite drop by placing one portal above another. Once the other guy's gained enough momentum, you move the top portal onto a high-up wall, sending your friend across the chasm.
If you get stuck, you can ping little pictorial messages onto your partner's screen. Use the D-pad and you can select from a range of pings and emotes, telling your partner what you want them to do.
They might be involved in their own possible solution though, so you shouldn't expect an immediate response. The final puzzle involves the first of the new innovations: the thermal discouragement beam.
Lethal to the touch, it can be reflected with a mirrored cube, turning into a weapon against GlaDOS's turrets. Naturally, GlaDOS finds this robot-on-robot violence abhorrent - never feeling the need to question her own attempts to kill you.