Killing zombies, much like reality TV, never gets old. Despite lots of copycats, we always line up to experience the next train wreck, or in this case, undead apocalypse. That happened with last year's critically acclaimed Left 4 Dead, Valve's terrifying first person shooter filled with flesh hungry monsters. Now, 365 short days later, there's Left 4 Dead 2. We've hungered for this game almost as much as zombies crave brains. Now that it's in our hands, the wait was absolutely worth it.

Four people versus thousands of zombies. Just the way we like it.

Similar to Half-Life (another one of Valve's popular franchises), the designers retained and built upon an already solid foundation. Like the original, you choose one of four characters and attempt to survive thousands of zombies. And like the original, you can play by yourself with three computer controlled heroes, or strategize online with friends. It's a speedy, frantic and brutal shooter, where you can go from confidant to overwhelmed in seconds.

That, thankfully, is where most of the similarities end. This time around, you'll play as four different characters: Coach, Ellis, Nick and Rochelle. Each controls exactly the same, but their unique stories add depth to their personalities. Valve also mixed things up with five episodes set in the Deep South: Dead Center ("Prices aren't the only things getting slashed."), Dark Carnival ("You must be this tall... TO DIE!"), Swamp Fever ("The only cure is dying."), The Parish ("This time it all goes south.") and Hard Rain ("Come hell and high water."). All of them feature the same final objective (make a last stand until help arrives), but the detailed scenery sets each one apart. Dark Carnival, for instance, not only takes place in a monster-infested amusement park, but also sports a final mission where you must battle zombies at a rock concert, complete with fireworks and music. Another, Dead Center, challenges you to navigate a shopping mall and eventually pour gas into a racecar to make your getaway, while scores of enemies pour through the entrances.

While on the subject of bad guys, you'll slaughter zombies of all shapes and sizes. There's the Horde, the hundreds of creatures (a crew that includes zombie clowns, zombies in hazmat suits and other outfits) that swarm you en masse, but you also have the Special Infected. Monsters from the previous game return, including the vomit spewing Boomer, the leaping Hunter, the long-tongued Smoker, the Witch (never mess with her) and the gargantuan Tank, but you must also contend with some new stars. The Charger, for instance, can ram someone into the nearest wall and repeatedly drive their body to the ground, while the nimble Jockey jumps onto someone's shoulders and steers them around, most the of the time into more zombies. Finally, there's the Spitter, a saggy-breasted female zombie that spews toxic green goop. Seeing as how the game has a nasty habit of sending these beasties at you, one after the other, we suggest staying frosty.

As if clowns weren't terrifying enough.

Fortunately, the game has a wide assortment of weapons, far more than its predecessor. Firearms include automatic and pump action shot guns, a few different assault and sniper rifles and a pistol, as well as different types of ammo (explosive, incendiary). Melee weapons also make an appearance, and you'll have a blast chopping off heads with a samurai sword, crushing skulls with a mallet/frying pan, whacking zombies with a guitar and shredding them with a rumbling chainsaw, among other toys.

Speaking of dismemberment, you'll see limbs fly all over the place. It's not uncommon to finish a battle standing atop piles of decapitated corpses, or watch as arms and legs sail through the air. There are multiple ways to snuff these creatures, either through stalking (definitely use a sniper rifle), going in guns blazing, setting traps (shoot a gas can to set them on fire) or just swinging away with a fire axe. It's a bloody good time that's significantly harder than the original, so don't expect to waltz your way through. Even on normal difficulty, the zombies put up a tough fight, forcing you to waste health packs, pills and new to the franchise, defibrillator units (revives fallen teammates) and adrenaline shots (increases speed and reload times). Thankfully, you'll almost always know when the crap's about to hit the proverbial fan when the soundtrack changes, right before the zombies appear.

If you choose to enjoy the game with friends, Left 4 Dead 2 has a series of entertaining modes. Survival is similar to each chapter's final rescue mission, except help never arrives. Instead, you see how long the team can go before dying. Then we have Scavenge, a new multiplayer game where one team plays as the Survivors, attempting to power a generator by finding gas cans littered about the map, as the others (playing as the Infected) try and stop them. Standard Versus also makes a return, where the four survivors attempt to reach the end of a level before the other team (again, as various types of Infected) conspires to murder them.

Although the game's a brain splattering good time, we still don't understand why Valve refuses to allow users to aim down the sights of a weapon, instead of always shooting from the hip. It gets the job done most of the time, but we feel everyone's accuracy would improve if they could line up their shots.

On top of that, the game may grow repetitive sooner than expected, simply because the objectives never change. You'll always battle the same monsters while achieving the same goals, and for that reason, we had no trouble putting the game down and coming back to it hours, sometimes days later.

Aside from those small complaints, Left 4 Dead 2 is one of 2009's best action games. Bring on Left 4 Dead 3.