This trailer also served as the in-game cinematic and it has a fond place in my memory. I have probably seen this cinematic more than any of the others combined. That is because my four friends who would play Left 4 Dead would stop more than once in a while to just watch the whole thing. That is pretty rare. Valve are pretty masterful at trailers, their individual class Team Fortress trailers are fan favorites and Portal has had some great cinematics too. What makes Valve so successful at trailers is that while they often tell a story, they use the mechanics of the game and capture the tone of their game brilliantly. This Left 4 Dead cinematic is the best example of that. Showcasing the different zombie types you will come up against, the use of pipebombs, the reliance on your squad and just the general insane panic that comes with playing through a campaign, this is an example of a cinematic trailer done absolutely right.