Thanks to my sister who's been watching this over and over again and reading up on the new Left4Dead 2, I've been informed that this is definitely a carefully crafted piece of intro.

The first scene where the 4 of them are exploring in the house is related to their working fields. The lady is a reporter (of some sorts)..guy who opens the cash register is a gambler/con-man, young guy is a student technician and the fat guy used to be a football coach (of some sorts).

Cool, right?

What's cooler I think it's their facial expressions! Can see it's better than the first one.

Tons of new zombies and new weapons.

Now I'm excited..!