Portal 2: Top 10 Test Chambers

We've picked out the ten chambers we found most challenging, memorable and just plain great during our single-player playthrough. And, for those of you yet to beat the game in its entirety or keen to relive the moment from another's perspective, we've also captured the solution to each.

In short, these are the puzzles that left us bewildered, frustrated and awe-struck in equal measure - and filled with admiration for Valve's fiendish ingenuity. This, of course, only represents our experience. We'd love to know how it was for you, so please let us know your standout, synapse-busting moments below. Meanwhile, here, in reverse order of misery/joy is our top ten.

And, if you haven't played Portal 2 yet then, y'know, spoilers.

8) Chapter 7-1

To prepare you for the game's later stages, where you'll be combining each and every mechanic Portal 2 has to offer, Valve likes to focus on each one in turn to brief the player on their full range of possibilities.

The first part of this chamber is all about Propulsion Gel. Spraying it to carry Chell over a ramp is clear enough; building up enough speed to burst from the floor and press a button suspended high in the air may take a little more figuring out.

7) Chapter 8-4

The test begins with a dramatic set piece as Wheatley wedges two chambers together. This bodge job leaves a gap traversable only via light tunnels, and on top of that you've got to factor in a cube that needs to come along for the ride.

The final piece of the puzzle requires the cube to be floated up against a button high on one wall to release the door. It's the clever narrative set-up, with its suggestion that Wheatley is making up tests on the fly, that makes solving it that much more satisfying.

6) Chapter 4-2

Most of the real mind-benders are reserved for the latter stages of the game, but this chamber is one of the most gruelling encounters before Wheatley's corruption.

The sheer scale of the chamber takes time to digest, and a patient, methodical approach is needed to proceed through each step of the multi-part puzzle. The video shows a relatively speedy solution that belies the frustrated torment of our first attempt.

5) Chapter 8-10

The end is nigh. Clever deployment of light tunnels secures the cube easily enough (you're a pro by now, right?). But the real mind-slam comes from working out how to cross the vast gulf leading, you hope, to the exit.

All the familiar elements are there before you: but it's the revelation that Propulsion Gel can be carried via the light tunnel that provides this chamber's eureka moment. It's knowledge that will come in handy come the final test.