Videogamer writes: "Finally, you can now download Portal to your Xbox 360. It seems ridiculous that 360 owners have had to wait a year to do so, forced (well, you should have wanted to, really) into buying Valve's brilliant The Orange Box compilation just to get a taste of one of 2007's best games. But there you go. That's capitalism for you... or something.
In the unlikely event that you have absolutely no idea what all the fuss, or indeed Portal itself, is about, allow us to bring you back up to speed. You wake up in a room without knowing why you're there - white walls, transparent doors, all very sci-fi - like cult horror film The Cube spliced with the video for Björk's All is Full of Love. A computerised female voice, one that you'll never forget, barks from some unknown origin, guiding you through the Aperture Science Laboratories test program. A portal appears, you walk through, but wait, something's up - you can see yourself entering it - or is that exiting it? Welcome to the mind-bending world of Portal."