Valve has released Portal 2 two days early, but only for those who bought it over Steam.
Valve has released Portal 2 two days ahead of schedule in the culmination of an Alternate Reality Game which saw players collecting hidden potatoes
and achievements from a number of indie games.
Players who found all 36 potatoes have been rewarded with a free copy of the entire Valve Pack, which includes all of Valve's previous games and Portal 2.
The ARG saw players competeing to get Portal 2 released ahead of schedule by rebooting in-game villain, GlaDOS. The game is now available to play immediately, though only if you've purchased it on Steam.
Players who pre-ordered a retail copy of the game will still need to await their physical copies, as will console gamers. Copies should be distributed or available to buy in shops on Thursday 21st April.
Portal 2 is the next side-story in Valve's classic Half-Life series, casting players as unwilling participants in a series of experiments run by Aperture Science - a rival of Black Mesa.
Read our Portal review
for more information on the game, or check out the Portal 2 video below. We'll have our Portal 2 review online shortly and until then you can let us know your thoughts in the forums