l4d glitches 1

in the apartments There is a glitch at the very beginning on the roof. Jump onto the ledge you are facing after the opening sequence, and turn 90 degrees to the right. From there, look down and you will see a very small white ledge. Make sure you have pills or a med-kit because Common Infected can spawn here. Jump onto the small white ledge and if done correctly, you should land on the ledge and lose about 95% of your health, so heal, and jump down. From here you can see a small area that the developers did not want you to see. CAUTION: Like the Infected, you will randomly die if you get near the hummer.