I got left 4 dead yesterday and played some single player to test if the vga card was still ok, it was. I played the first 3 champters of the No mercy campaign in advanced difficulty, I must say that the AI is pretty good and that the Romero movie feeling is very well done too. The only thing that bothered me was the fact that the system which respawns enemies depending on your lvl of gaming, wanted me to encounter with the witch, in a matter of 10 minutes like 4 witches were respawn but I was very careful and didn't fight any, but I had tu turn off the flashlights a great part of chapter two an three. I knew about the witch instant killing move because Jeff warned us in his blog post about Left 4 Dead mp tips.
When I was in chapter 3, in the sewers, after we arrived a room with ammo and a medikit, we had to go through a narrow section, at the end of it, a tank, a boomer and a regular zombie horde appeared, what made me angry was the fact that the Tank could go through the corridor although he is huge and his arms were like inside the walls, we died there and i was very angry, but well, that glitch is very common so I can forget about it.
The game is great and i can't wait my friends to get it, to play all the campaigns in coop in max difficulty with them, I was speaking with one of them by gtalk and he said "don't play anymore, let's explore all the maps together when we all have it", so i will not play it for a while but that stylish desktop icon is there saying "come on let's shoot some zombies in the head".

But well, i will have to wait, now I am installing Opposing Fronts which i got before the blackscreen problem began, I am very anxious to play the Axis campaign (Nazi Zombies!!, no wait, alive Nazis XD), all my life a ww2 game was about being the allies, but this time I think it will be cool to enjoy some German side of the story, they had the coolest army, that heavy tanks and the awesome soldier outfits.