I loved Left 4 Dead. Sure, it was over too soon, and I don't agree that four is necessarily the magic number for co-op, as Valve would have you believe. But the game was a classic example of how cleverly constructed co-operative titles can be immensely popular whether on console or PC. And after all, zombies are just way too much fun to kill.

It's been nearly a year now since the original Left 4 Dead was released, and in the meantime there's been a veritable horde of controversy over Valve's intended support path for the original game, versus the development of the second. Many people rightly assumed that Left 4 Dead would get a heap more content before the sequel was even mooted, concerns that Valve addressed with the Crash Course content update last month. It's now irrelevant whether that was sufficient to quench the thirst of the community because Left 4 Dead 2 will be released on the 20th November in New Zealand, it will carry a full retail price, and if the demo is anything to go by, you will buy it.

The demo allows you to play through two parts of The Parish, one of the five campaigns announced for the sequel. The Parish is set in New Orleans, and the action starts with the affable NPC ship captain Virgil dropping the quartet off at a deserted dock. From here, it's a tense street-to-street fight, followed by a march through a large park and on to a construction site for the finale.

The best part of the original Left 4 Dead was the co-operative nature of the game, and none of this has changed in the sequel. You'll still be required to heal your team-mates, and rescue them from all manner of nefarious infected, but what is immediately obvious from the outset is that Left 4 Dead 2 contains a bunch more content. Melee weapons have been enhanced considerably - where Left 4 Dead limited you to using environmental objects such as oxygen cylinders, gas cans and propane tanks to strategically mutilate the infected, Left 4 Dead 2 introduces the samurai sword, frying pan, chainsaw, cricket bat, crowbar, machete, nightstick, axe, baseball bat and guitar, as well as the conventional pipe bombs and molotov cocktails.

Primary weapons have been enhanced too - you'll be able to pick up a silenced SMG, AK-47, grenade launcher, semi-auto sniper rifle and a magnum in addition to all the weapons from the first. The AK-47 is particularly enjoyable in the demo, it has a slower rate of fire than the assault rifle, but does a heap of damage even at long range. As if that wasn't enough, you can even pick up explosive as well as incendiary rounds for various weapons, and target your prey using laser sights!

To prevent the game from becoming a mindless turkey shoot (or at least, more of a mindless turkey shoot), Valve have added to the army of the infected with several new bosses. The Jockey is particularly annoying, as he seems to appear out of practically nowhere and attach himself to your back, prompting your three companions to immediately turn around and unload their weapons at you. The Jockey will also steer you towards other mobs of infected at the whim of the AI director, and this resulted in a pretty spectacular wipe for myself and my online companions, the details of which need not be repeated here.

The Charger is about the size of The Boomer, however has a hugely mutated arm and runs at an incredible speed - usually right for you when you're trapped in an alleyway and have nowhere to go. He's particularly good at slamming your lifeless corpse on various environmental objects - dumpsters, walls, the sidewalk - whatever is likely to drain as much health from you while your friends stand around trying to hit him.

The Spitter vomits waves of toxic green sludge that does significant damage to your health. Oh, and The Witch now wanders around in daylight, and sounds a lot freakier than before, if that's even possible. It's nice to know the phrase "don't startle the witch" is likely to make a popular comeback at LAN events over the festive season.

As alluded to previously, much of the gameplay remains the same - this is a good thing, as there wasn't really anything wrong the first time around. What Left 4 Dead 2 brings to the party is the additional content Valve probably should have released as part of their ongoing commitment for the first title. That old chestnut. In any case, we've been promised that the campaigns will be longer this time around, and they're also throwing in a new "Skirmish" mode allowing four-on-four tactical gameplay with dedicated map support. Valve have also hinted at a "Realism" mode designed to test the limits of players, no doubt more about this will be revealed over the coming weeks.

The demo does have a different feel to the original, although perhaps that's down to the setting of The Parish, which is generally much brighter than previous Left 4 Dead campaigns. Nevertheless, the game is well on track to impress the hell out of anyone who sunk some serious time into the first, and really, that's all we want from our sequels. Listening to Australians complain over voice chat about the lack of any gore in their demo was just the icing on the cake.

Roll on November!

the L4D2 demo will be available November 3rd for PC and Xbox Gold members, while Xbox Silver members will get the demo on November 11th, 2009 (US)