The co-op works better than ever, the atmosphere is dense and the scale is more massive than expected.
Since the original, the apocalypse hasn't abated and once constant remains: lots of pissed-off zombies. In keeping with the theme, four survivors who each fall into a neat little descriptor-everyman, cynic, enthusiast, and eldest as leader-have to watch each other's back in order to progress through the five scenarios to get to rescue. Along the way, hordes of zombies will impede their progress and imperil their lives, particularly the Special Infected returning from the first game.
The Boomer, Smoker, Tank, and Hunter are still up to their nasty tricks, but Valve have included three new Special Infected specifically designed to deal with players who've become accustomed to fending off hordes by sticking close together and being stationary. These three new infected are designed to divide the survivors and force them to move.
The Charger will ram through the survivors and slam them to the ground while the Spitter shoots corrosive acid. As a change of pace, the diminutive Jockey leaps on a survivor and can actively control them once initiating the attack. On his own, he's not much of a threat, but the Jockey's real danger comes from steering the survivor into things like fire, other infected, or near ledges.
Not to be out-gunned, the survivors have some new pieces of ordinance. While the "new" primary weapons boil down to shotguns, sniper rifles, and automatics with permutations on damage and rate-of-fire, it's the addition of melee weapons that prove to be one of the most unique additions. There's still the option to pick up two pistols, and players are given the opportunity to swap those out for things like fire axes, crowbars, and skillets.
Each feels unique and the feedback on the different melee weapons is realistic. The stopping-power of the skillet is much different from the swinging of an axe. As an alternative to pistols, they're most effective when you find yourself surrounded by hordes of zombies-which happens quite a bit.
Chainsaws and grenade launchers become the default "uber" weapons since they do a lot of damage, but have drawbacks in the form of running out gas and user-damage. Still, there's no arguing with the appeal of blowing up a dozen zombies into chunky bits or turning a horde of them into cold cuts with the chainsaw.
However, all these additions are just that-more stuff. Are there any real changes that affect the gameplay experience? In a word: sorta. The campaigns are much more fleshed out with stronger locales. You have five scenarios to work through and there's something of a unifying narrative. Things officially start off in Savannah, Georgia and end in New Orleans, but there's nothing preventing players from choosing any scenario they wish.
There are still plenty of sections where players must alert the horde in order to proceed and simply dig in their heels in order to survive, but the addition of gauntlet-runs makes things much more frenetic. These sections involve players alerting the horde and running for dear life as dozens of zombies chase after them. The gauntlet doesn't let up until a player finds a switch to end the insanity.
Unfortunately, for a large part much of the gameplay remains unchanged. Sure, there's more stuff, but what winning comes down to do is listening for musical cues, watching each other's back and conserving supplies.
Like the first, most of the replay value is found online. Survival mode is included right from the start and involves players fending off insane amounts of zombies for as long as possible, though don't expect to last more than ten minutes, tops. The main attraction is Versus mode, where four survivors and four Special Infected go head-to-head. Players take turns between sides, and whoever makes the most progress wins.
Playing as the Special Infected is quite a treat and deviates from the usual ho-hum online deathmatch-style gameplay. Success is all about looking for opportunities to split-up survivors and multiplying the pain. A Jockey will steer a survivor into a pool of Spitter acid or a Boomer may vomit and get a horde to attack a survivor being strangulated by a Smoker.
Two new modes are also available to play: Realism and Scavenger. The former is essentially expert difficulty cranked up to eleven. Startling a Witch becomes more dangerous since her attack results in an instant-kill and the regular infected take and dish-out a lot more damage. As if that weren't bad enough, there are no identifying halos around your teammates. Keep track of them or else you'll pay for it later.
Scavenger requires much less time to play. There's a finite time-limit that can only be extended by pouring gas into a generator. It's much more to the point than the other modes and offers just as much fun as Versus does. Players stuck in the role of Special Infected will have to stop the survivors from filling the generator while the survivors must pour as many tanks of gasoline in as they can.
Don't have online privileges? Well, at least there's splitscreen two-player and if that fails you can always play with three bots. It's an unspoken truth that the maximum enjoyment one can get from the Left 4 Dead 2 experience is if you go online. Most of what makes the game great can't really be replicated offline.
That said, there's nothing inherently wrong with the AI behavior. Survivor bots will stop to rescue you, heal you when you need and have decent aim. However, you don't see the on-the-fly strategies that make online play so much fun-so you'll find that the dynamic experience becomes flat quickly. The bots will also never use explosives, something Valve really should think about changing with their next update.
The fundamentals may not have changed so drastically, but Valve has taken a look at how players performed in the first game and tailored the sequel to challenge them and develop new, interesting strategies to combat the infected. There's much more crammed in than the original with more additions coming down the pipeline. Left 4 Dead 2 is an insanely fun co-op and competitive online experience, and that's a great similarity to have with the original.