Portal's tricksy world plucks at some fascinating video game threads

If you ask me, Portal’s signature moment involves putting a portal in the ceiling and another portal in the floor just below it. Thump, thump. These portals, for the uninitiated, are basically two sides of the same magical hole; walk through the orange portal and you emerge through the blue portal. In the game’s deliriously arch fiction you are testing a device that projects these holes, allowing you to do unusual things with space as a result.

How unusual? With the floor and ceiling set-up, you have created an extremely short tunnel, the height of the room you’re in. And yet it’s also a tunnel you can fall through forever, that single room zipping by again and again like the repeated domestic background in a Tom and Jerry cartoon.

Here is the thing, though. Over a decade after Portal’s release, just thinking about Portal can be a bit like falling through that simultaneously brief and endless tunnel. Oh, to make a Slinky of your thoughts! Blue becomes orange, distance becomes time, ceiling becomes floor becomes ceiling again. Absolutes clash against conflicting absolutes.

Let me give you a quick example. Portal is a sandbox. It’s a suite of often nearly empty lab rooms for you to move through as you play with one of gaming’s most thrilling toys – a gun that allows you to fire out two sides of the same hole onto any applicable surface and then screw around with what you have made. But listen: it’s also the consummate anti-sandbox, because these empty rooms are home to one of the most exacting puzzle games ever presented, where everything from lighting, geometry, textures, and the voice in your ear – which we will return to in a minute no doubt – are guiding you endlessly towards one correct, if sometimes torturous, solution after the next. Because Portal wants to show you such clever stuff, and specifically because it gives you so much potential power in order to show you that stuff, it has to become restrictive, too.