Last year Left 4 Dead unleashed a harrowing and entertaining vision of what it's like to be on both sides of the zombie apocalypse. Whether you were shooting your way through hordes of infected (the preferred nomenclature) en route to possible rescue, or scheming with your fellow superpowered zombies (an acceptable colloquialism) in an effort to choke, eviscerate, and otherwise kill the intrepid survivors, Left 4 Dead was enormously fun. The only real drawback was the shortage of content. Left 4 Dead 2 does not have this problem, offering five new campaign maps that can be enjoyed across five uniquely engaging game modes. These campaigns are more diverse, more atmospheric, and more exciting, thanks largely to the stellar level design. Left 4 Dead 2 also improves on the original in almost every other way, featuring new weapons, new items, new enemies, and new survivors that make the game richer across the board. Though the core action remains largely unchanged, the widespread enhancements make Left 4 Dead 2 even better than its impressive predecessor. This is one zombie apocalypse you do not want to miss.

The heart of Left 4 Dead 2 is the five campaign maps that take the survivors through a wide variety of terrain in the Deep South. From murky swamplands to a creepy carnival ground, from flooded suburbs to claustrophobic city streets, every environment is detailed and immersive. Clever design touches abound, some of which are clues that show you which way to progress. It's deceptively easy to get turned around, especially since you aren't the only ones who have been leaving piles of bodies around. Left 4 Dead 2's environments help tell a story, and as you travel through the remains of a massive government-organized evacuation effort, you get a better sense of how it all went down. The campaigns now string together to make one long adventure, and though the oppressive, desperate mood seethes more potently this time around, there is still plenty of levity and high-impact excitement. Well-timed survivor quips make trudging through zombie-infested swamps a bit less nerve-racking, and thunderous rainstorms make a tense final stand (the moments right before your rescue) even more dramatic. The sound design is a standout once again, filling the air with eerie strains and helpful cues, as well as conveying the full range of the survivors' emotions. This rich atmosphere is enhanced by the wider variety of choke points and final stands, all of which give the campaigns their own unique pace.
Into these grim landscapes come four new survivors. This new crop is more lively and talkative than the first bunch, and Ellis' good-ol'-boy stories about crazy stuff that he and his buddy Keith did one time are bound to make you chuckle. There is a new crop of guns as well, including multiple versions of pistols, shotguns, submachine guns, and assault rifles. These different flavors go a long way toward spicing up the gunplay, but the standout new addition is the melee weapons. A fire axe, a crowbar, a cricket bat, and a frying pan are just some of the objects you can use to slice, bludgeon, and decapitate your enemies. They take the place of your secondary weapon, but you still have a sidearm you can whip out if you are incapacitated. Using these weapons forces you to get up close and personal with the infected, affording you a better view of the carnage but also putting you at higher risk. Still, nothing stops a horde like a katana-wielding survivor standing tall in a doorway. Melee weapons are a great new strategic asset and add a very enjoyable new dimension to combat.

Part of the reason melee weapons are so fun to use is that the infected die in a lot of gruesomely entertaining ways. Dismemberment and gibbing have been ratcheted up in Left 4 Dead 2, so you'll be chopping off limbs and blowing holes in zombie abdomens like you were born to do it. The common infected models are more diverse and detailed, and there are a number of tougher variants that pose a bit more of a challenge. Some of them can take more damage, like the ones in hazmat suits and riot gear, while others move more quickly and can obscure your view, like the swampy mudmen. These "uncommon common" won't throw a huge wrench in the works, but they add some welcome variety and help further diversify your enemies.

The foes that will derail your progress are the special infected. These zombies have superpowers that make them seriously dangerous, and all the baddies from Left 4 Dead make an encore appearance. There are a few new nasties to contend with as well, including the Jockey (jumps on your head and steers you off course), the Spitter (shoots a pool of deadly acid on the ground), and the Charger (rams into you, carries you away, and pounds you into the ground). There's also a variety of Witch that actually walks around as opposed to just sitting and weeping, and she rounds out the formidable roster of special infected. These enemies are tricky to contend with in the field, especially when a few of them descend on you at the same time. They are even nastier when they are controlled by your fellow players. One of the best parts of the zombie apocalypse is being part of the problem, and unlike its predecessor, Left 4 Dead 2 makes every campaign available for Versus play right from the start. Playing Versus mode allows you and your team to spawn as special infected and coordinate attacks in your efforts to make sure the survivors don't make it out alive. Nothing eases the frustration of being dragged away from your fellow survivors by a Smoker's tongue like jumping on a survivor's head and jockeying him into a pool of burning acid. Versus mode plunges you into an engaging mix of competition and cooperation as you and your team alternate trying to survive and trying to kill.

For those who don't fancy this sort of competition but are looking for a challenge beyond the range of difficulty offered by the Campaign mode, the new Realism mode is the place to go. Here you'll play through the campaigns with many of the game-y aids removed. There are no glowing outlines around your fellow survivors or around helpful items, zombies are tougher to kill, and dead comrades won't respawn until you reach the next safe house. You won't know how much you rely on the glowing outlines until you walk into a clearing and realize you are utterly alone and have no idea where your friends are. Or worse, what happens if you get grabbed by a Smoker and dragged away, but no one sees it? Realism mode very effectively ramps up the tension, and you'll be even more thankful for the new equipment items that offer help. Adrenaline shots not only give you a health boost, but they allow you to heal and rescue teammates more quickly. Defibrillator pads allow you to bring dead survivors back to life, and explosive and incendiary ammo packs help make sure you don't need defibrillator pads as often. And then there's the bile bomb, which lets you spray enemies with the Boomer's horde-attracting vomit. If you chuck this on the Tank, you'll get some help killing him. And if you chuck it over a ledge or into a fire, you'll kill a lot of infected and get a good hearty chuckle to boot.
Rounding out the package are two modes that offer all the excitement of Campaign and Versus play in a fraction of the time. Survival, introduced as downloadable content for Left 4 Dead, is like playing a last stand in which rescue never comes. Survivors try to stay alive on a well-stocked map against endless waves of infected, and they earn medals and leaderboard-worthy times for their troubles. Without the joy of escape, this mode isn't as satisfying as its longer counterparts. The same is not true for the new Scavenge mode. Here, survivors try to collect gas tanks from around a map and pour them into a generator to add more time to the dwindling clock. A team of infected try to stop them and kill them. This mode more adeptly mirrors the frustrations and rewards of Versus mode. On the one hand, you have the challenge of survival and the thrill of each can successfully deposited; on the other, you have the task of foiling the survivors' well-armed efforts and the grim satisfaction of taking them down. Each team plays both sides per round, and the first to three round victories wins. The short format makes it easy to enjoy in quick sessions, though more than likely you'll be tempted by rematch after rematch.

Though it comes a mere one year after the original, Left 4 Dead 2 is a much better game and much better value. The new campaigns and unique game modes offer more variety and more longevity, while all the other additions and tweaks make the already great gameplay even more enjoyable. Even the AI has improved a little bit, and while they still aren't big on using pipe bombs or Molotovs and are prone to missteps, they seem to have a better grasp of tactics and will follow you a bit more closely. Still, Left 4 Dead 2 is best enjoyed with friends, and every mode is seamlessly integrated online. Though the core gameplay remains pretty much the same, there is more than enough new content and improved action to make this zombie apocalypse highly recommendable.