Valve announced today that they've released the second downloadable content pack for Left 4 Dead. The "Crash Course" update is available for both the PC and Xbox 360.

"Crash Course" is said to connect the end of the "No Mercy" campaign to the beginning of "Death Toll." The new cooperative campaign comes with Versus mode support as well as new maps for Survival mode. The game has received a few tweaks as well, such as a recharge timer for infected teammates and reworked item spawn mechanics.

To celebrate the release of the new DLC, the PC version of the game has been marked down to $15 (50% off the normal price) on Valve's digital store Steam. The discount will last until October 1st.