Valve has kept its promise and released the hotly anticipated major update for Left 4 Dead, as promised a little while ago. The update is now available automatically via the Steam service and it is completely free, which makes it even better!

Just as announced, the update allows for the Versus mode to played in the Dead Air and Death Toll campaigns and it also adds a new Survival mode in which you have to battle waves of brain thirsty zombies – something which, as you will see, is very, very difficult.

Also, if you still haven’t purchased this wonderful game yet, you can do it now for a lower price, since Valve seems to be ready for celebration: $39.99 for the entire package!