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.

Axe self-defense just doesn't have the same ring to it.

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.