Valve’s hugely anticipated first-person puzzle game Portal 2 has launched on Steam and is currently retailing at a price of £29.99. The game doesn’t launch on PlayStation 3 and Xbox 360 in Europe until April 21st, although it is currently available on all three platforms in North America. This is also the first of Valve’s games to launch simultaneously on Windows and Mac using the SteamPlay cross-compatibility functionality.

You can still pre-order Portal 2 on Xbox 360 and PlayStation 3 from Amazon for only £32.70 here and here. It’s worth noting that activating your Steam account with the PS3 version in the game will allow you to redeem a free copy of the PC version as well. Amazon are also offering the PC version of Portal 2 at retail for £24.91 here, significantly lower than the Steam version. You can find the game on Steam here. To find out more about Portal 2, you can check out the game’s zConnection page here.