The first L4D introduced a fun new A.I., and this was the main attraction of the game, but the new star of L4D2 is undoubtedly the new melee combat system. This system marries melee combat such as that found in Dead Rising to the L4D2 gameplay. Like Dead Rising, the L4D2 melee combat system will allow you to use a number of melee weapons to cleave, brain, and brutalize zombies in a number of creative and sometimes comical ways. The system adds a number of different melee weapons that weren’t in the first game such as a baseball bat, frying pan, a katana sword, the very fun chainsaw, and many others. It can get quite messy at times, but that’s what makes it so fun. Melee combat opens up a whole new way to play and is really the biggest change since the first game as in L4D your melee skills were limited to simply knocking the zombies back.

As I just mentioned, Valve added a lot of other new weapons and items to L4D2, no doubt a result of player displeasure with the small amount in the first game. Let’s take a look at some more options. There are a number of new firearms that can be upgraded with laser sights, as well as various types of ammo. There are also new throwing objects like the Bile Bomb, a bomb made up of the bile from a Boomer, which is a creature who spits bile that attracts infected hordes. This item comes in handy against stronger enemies as you can turn the undead against them. While not a weapon, you can also get your hands on defibrillator paddles, which come in pretty handy for bringing a fallen ally back to life. (WTB Rez?)

This time around the game takes place in the southeast United States and the new bunch of characters are a bit more lively and talkative than their predecessors. The funniest, at least to me, is Ellis, a good ol’ boy who can make some rather comical comments throughout your campaign. But each character has their own personality and will add dialogue at various moments throughout the game.
The new campaign mode offers five new and unique campaign missions with Dead Center, Dark Carnival, Hard Rain, The Parish, and Swamp Fever. Each one features between 4-5 maps ranging from escaping the dark carnival to trying to make your way to safety amidst heavy storms in Hard Rain. Hard Rain is my favorite as the A.I is capable of controlling a new weather system, so not only do you have infected to deal with, but you also have the possibility of fierce wind and driving rain as well as decreased vision.

Each campaign offers a unique experience and setting. In Dead Center, the first campaign, you will find yourself escaping a hospital and eventually the old cliché of classic zombie movies, a mall, but with other campaign settings you’ll find yourself in a carnival fighting zombies on a roller coaster and you’ll even eventually find your way down to New Orleans.
There is a bigger emphasis on teamwork in L4D2 as you’ll need to communicate and work with your team if you want to survive. The crescendo events (certain events in-game that you must complete to advance) work a bit differently than they did in the first game. In the original L4D, these events usually played out with a couple of hordes rushing the players and once they were dead (barring the end of campaign events), the players were free to move on, but in L4D2, these events may require you to complete a task, or shut off an alarm, all while the infected are coming at you virtually non-stop. In one instance I had to get a barricaded man some Cola to move on, but to do so I had to trigger an alarm that kept me under constant siege from the undead while I tried to get it back to him. Moments like these are pretty tense and require good team work to make it through quickly.
While L4D2 comes with the option to play the campaign solo, it’s best done with a group; L4D2 was made for group play and that’s how it’s best enjoyed. You can gather players in a game room lobby before you set out on your adventure, much like putting a party together for an MMOG dungeon run. However, if you’re set on doing the campaign alone, the A.I. is good to play with and they do a decent job at following your lead, but like the last L4D, the A.I. doesn’t care too much for picking up and using pipe bombs, Molotov’s, or other useful items you need against the infected hordes. They’ll still use melee weapons and guns, but their inability to use the aforementioned items is one huge disadvantage they have that playing with a real team doesn’t. While the new A.I. allies do a decent job following you around, they can still get tripped up at times and this can be problematic if one or more of your party get into trouble.
New infected creatures make an appearance to add to the challenge of both single and multiplayer mode. The Spitter spews a toxic fluid on the ground dealing area of affect damage and can incapacitate a survivor pretty quickly if they are foolish enough to keep standing in the green goo. The Jockey can pounce on the head of a survivor and steer them away from their group and into all kinds of trouble. These guys are pretty weak, but if they catch a survivor alone, that’s where they shine. Lastly, the Charger (my personal favorite) is a larger creature, almost like a mini-tank, with a huge arm. He’s capable of charging into a survivor and carrying him away from the group. The captured survivor is then pounded into the ground by the creature’s huge arm. These new infected offer a lot of challenge and are really fun to play in versus mode. The classic infected return as well with the Hunter, Boomer, Tank, and Smoker.

My biggest disappointment with the original L4D was the fact that there was no real storyline and the gameplay was set up to follow a straight setting which played out almost like a B-movie. While L4D2 has a bit more story connecting the campaigns and building more personality for its characters, it still plays out much like the original. There is no real story arc and each campaign plays out the same as its predecessor where you make your way through each map until your eventual escape. For what it is, a cooperative action zombie shooter, L4D2 is pretty good, just don’t expect any intricate story arcs.
The only other major issue I have is the fact that there are a couple of bugs in the game at the moment that can cause it to crash without warning. Valve is aware of this problem according to their forums, but it still can be quite a nuisance. I have experienced this in the game, but it only seems to occur when I play solo and slay a witch. I never ran into this in multiplayer mode, so with any luck this will be patched soon. How this one snuck past QA is anyone's guess.