Metro 2033 free for PC users

THQ is giving Metro 2033 away free on Steam to those who like the Metro Facebook page.

Once you like the Facebook page, a Steam code is revealed which can be redeemed to download a free copy of the game.

You'll have to act quickly if you're interested, as the offer only runs until 16 December.

A sequel to the first-person shooter, Metro: Last Light, is set for a release sometime in 2013.