SWhat we'd seen of Left 4 Dead at Games Convention, we'd mostly seen before. Just prior to E3, we played through the entirety of the game's first scenario, a sprint to the roof of a hospital through a cluster of zombies, where the four survivors await evacuation by helicopter. And, should you be too lazy to check out our impressions from that gameplay session, we'll just tell you it was tight, adrenaline pumping stuff. There were only a few noticeable changes in the Games Convention build. It was our first look at the updated models and skins for the four playable characters, each given a new coat of paint to help further distinguish them from the hordes of undead. But it was the new touches of detail — and the promise of more Left 4 Dead — that sparked our interest once again.Taking a page from the book of Portal (and Half-Life 2, really), Doug Lombardi from Valve told us that Left 4 Dead would feature subtle hints fleshing out the game's back story. Graffiti and scratches peppered the walls of the zombie filled city, with messages to and from survivors scrawled upon the walls of the game's safe rooms. Since we don't know much about the who, what, when, where and how of the zombie apocalypse the game is set against, we look forward to rooting out the details. And like Team Fortress 2, Valve plans to feed Left 4 Dead players with regular updates. New scenarios are definitely in the works as future downloadable content through Steam, but new monster types and new weapons sound like a distinct possibility. But we'll save our fervor for Left 4 Dead's bonus content for later. For now, we just want the game.