Left 4 Dead is now live. One of the best things I can tell you about it is this: there is nothing else like it.

Whatever your opinion on its viability as a single-player game (it'll help if you're inclined to chase achievements on Steam or Xbox Live) or its long-term appeal (only two of the four campaigns support the Versus mode that allows humans to play as monsters), you can't deny that it knows its zombie movie moments. From the comic relief quips ("Great, so everybody except us is either a zombie or an asshole...") to the graphic gore (no one does headshots like Left 4 Dead), this is a triumphant combination of horror and gameplay.

Like Capcom's zombie masterpiece Dead Rising, it might be frustrating to people who expect something a bit more accomodating from their games. There's not much to Left 4 Dead beyond the challenge of getting from point A to point B with no certainty about what's going to happen in between. The pace is awfully frantic (Valve has clearly come down on the side of fast zombies), the gunplay can get sloppy, and everyone else on your team is a frickin' idiot. But you're guaranteed iconic horror movie moments: a line of zombies rounding a corner so fast they curve out and lean in; the basso profundo rumble of an approaching tank when you're least ready; the eerie sob of a witch bringing everything to a screeching halt; and that terrible moment at the safehouse door when you know you made the wrong choice when you decided to just run for it instead of holding your ground a few seconds more.