One of the most interesting things about Valve's upcoming zombie pandemic shooter Left 4 Dead is the way the game is structured. Instead of a single story that follows one player from beginning to end, Left 4 Dead is divided into four "movies," which are essentially minicampaigns intended to be played over and over with the aid of four-person co-op and a remarkable AI system that assure no two experiences are the same. Up until this point, Valve has shown only two of the game's movies, the hospital-focused No Mercy and a run through the woods called Blood Harvest, but we recently had the chance to play through a third: Dead Air.
Part of the reason these campaigns are called movies is their clocking in at about an hour and a bit of plot guiding the action toward an ultimate destination. In the case of Dead Air, your team of survivors needs to make its way to the local airport after seeing hope in a cargo plane flying overhead. Before the action starts, you'll see hints of the movie's climax in the form of a movie poster that adorns the loading screen. The game's four playable characters stand in front of a ravaged airport with a tagline that reads, "Their flight just got delayed. Permanently."
Despite the cheeky tagline, there is hope for your team of survivors if you can withstand the literally thousands of zombies standing between your starting point and the airport. The first chapter begins in a greenhouse with your team overlooking a few shambling undead meandering from plant to plant, oblivious to your presence. But once you get equipped with some weapons and health kits and jump down, the slaughter starts and the "AI Director" immediately begins to review your performance. Over the course of the movie, the AI is constantly working to see how well your team is doing. If you're plowing through the zombies, you'll find your screen filled with dozens more enemies--often popping out of less expected spawn points like ceiling rafters. But if you're not doing so hot, the game will oblige and tone things down a bit.
The key to success in Left 4 Dead is teamwork. Your team of survivors needs to stick close together and keep close tabs on everyone's health and equipment to make sure first aid kits and other items are given to those in the most dire need of them. It's easy to get lost when your team fails to stay close, and doing that is often quite difficult in Dead Air. This movie is unique among the others we've seen in the way it keeps you on your toes by rapidly fluctuating between narrow, cramped corridors and wide-open spaces susceptible to floods of the infected. After making it through the relatively confined first and second chapters (Greenhouse and The Crane, respectively), the third chapter finds you in a construction site with a daunting amount of open space. It's easy to get separated from your teammates here when the zombie horde arrives, so you'll need to find one spot in this field of construction equipment and unfinished buildings and work together to stem the flow of hungry undead.
The fourth chapter is called The Terminal, which is when your team finally arrives at the airport. This chapter is when things start getting really tough. Whether it's crawling through cramped baggage transportation beltways, avoiding metal detectors so they don't sound and trigger waves of zombies, or navigating the maze that is any modern American airport, you're confronted with a new series of challenges that don't exist earlier in the movie.
But all of that's nothing compared to Dead Air's climax. Once you've escaped from the gate, you'll make it out onto a destroyed runway with all manner of airplane wreckage strewn about. The state of the situation is really driven home by a few scripted but thoroughly impressive sequences of destruction happening in the distance. This final chapter is when you'll see the most zombies coming your way, as each movie doesn't really have a boss battle so much as it stages one final assault on your well-being with an unprecedented zombie horde threatening your rescue. In this case, you need to stave off the horde while the aforementioned cargo plane refuels, which proves to be a long and nerve-wracking process. If you're successful, you'll find salvation and see a rolling credit sequence every bit as cheeky as the movie poster, right down to fine print that tells you the number of "zombies killed in the making of this film."
This session with Left 4 Dead was unique in that we had the chance to play a single movie in two very different ways: once in single-player on a PC, and a second time with four people on the Xbox 360. In single-player, your teammates are replaced by AI-controlled bots. Oddly enough, this situation proves to be far more survival-friendly than playing with human teammates. Aside from having a bit of trouble recognizing the dangers of fire and wasting their ammo by shooting zombies near a pipe bomb you've just thrown, the AI teammates are very helpful and good at sticking close by your side. We had a much easier time making it to the end without all that pesky human error getting in the way, but at the same time that sense of human cooperation is what makes Left 4 Dead so much fun.
In terms of platform differences, the PC version clearly looks better, but for that we can thank Valve's roots as a PC developer. Still, the 360 version looks great by the console's own standards and controls very well. Deciding which version to pick up will be tough, whether you want to go with the 360's ease of matchmaking with Xbox Live or the PC's slicker visuals and greater potential for postrelease updates. You can look forward to seeing our review for both games when Left 4 Dead arrives on November 20.