Left 4 Dead 2, a zombie survival cooperative first-person shooter developed and published by Valve on Steam for Linux, is now free to play, at least until Monday.

The official launch of Left 4 Dead 2 for the Linux platform has prompted Valve to offer all users the possibility to play the game, for free, until Monday 10AM Pacific Time.

“Celebrating Left 4 Dead 2’s official release on Linux and America’s Day of Independence, we’re putting L4D2 on sale for a stunning 75% off and it's free to play all weekend!

“We know people have a busy weekend ahead of them with BBQs, sack races, blowing fingers off, and other fun summer time activities, so we made it a little more enticing to give it a try this weekend. We are making L4D2 free to play until 10am PST Monday morning,” reads the official announcement on Steam.

Valve also reintroduced a new achievement for this weekend, which can only be gained when the game is free. The achievement is called Good Guy Nick (Play games with free weekend players and helps them survive a campaign).

“Who is a free weekend player? You’re going to have to talk to each other to find out or you could always let your friends know Left 4 Dead 2 is out on Linux and is free this weekend. After all, the zombie apocalypse was made to be fought with friends.

“All kidding aside, it is going to be dangerous outside this weekend. Stay indoors. Play some L4D2,” ends the Valve announcement.

Left 4 Dead 2 is technically out of the Beta, but Steam will still show two versions of it. If you haven't installed the game yet, you have to play the one with the Beta inside the Brackets.

Even if the game is free to play all weekend long, Valve is also offering everyone the opportunity to buy the game with a 75% discount.

Happy zombie hunting!