The free 24-hour trial of Left 4 Dead (PC) is being extended through the night. The free trial includes access to the recently released Survival Pack DLC, which introduced a new multiplayer game mode and two additional Versus campaigns. Those who wish to give L4D and the Survival Pack a free try now have until Saturday at 5 pm GMT, with no obligation to purchase. Those who decide to purchase the full product and do so this weekend will save 40% off the regular price.