The best co-op shooter i've ever experienced. It gratly improves on the original Left 4 Dead
Campaign mode and Survival mode see no changes with the sequel. Versus mode has been changed a bit. There is now a distance bar on the score/health screen that monitors the survivor's progress in the current chapter. In scoring, the health bonus has been removed and the scoring system has been changed a bit. Other than that, it still plays pretty much the same.
Realism mode is a new form of Campaign mode. It is meant to mimic a real zombie apocalypse, therefore, the silhouettes and names of the other survivors are removed when playing. Teamwork is stressed in the entire game, but moreso in this mode because one step in the wrong direction could leave you dead. Scavenge mode is a new competitive mode in which a team of survivors has to collect gas cans form a map and deliver them back to the generator. There is a time limit on this mode and the more gas cans you collect and bring back, the more time is added. While the survivors are doing this, there is a team playing as the infected trying to stop them, once the round ends, the teams switch. It is a lot of fun and a very good addition to the game.
On top of the new modes, new weapons and items were added. They added a new magnum pistol, an AK-47 assault rifle, a 12-gauge shotgun, a new sniper rifle, and a whole array of melee weapons to use: A chainsaw, frying pan, guitar, nightstick, crowbar, fire axe, machete, katana, cricket bat, and baseball bat. In the grenade slot, they added a new item, the Bile Bomb. It's basically a jar of boomer bile that you throw and it attracts the zombies to that spot. What makes it different than the pipe bomb is that you can throw it on special infected, such as a tank, and all of the zombies will attack the tank. They also added an adrenaline shot item that gives you a small temporary health boost but you run and perform all actions faster for a period of time. Next, they have added a defibrillator that you can use to revive dead survivors. and Lastly, they have added special ammo boxes. Once deployed, they will supply each survovir with a single clip of either incendiary ammo or explosive ammo, depending on the box.
Next, the new special infected. The original special infected, hunter, smoker, boomer, tank, and witch all return. The witch, on certain maps will walk around instead of sit on the ground however. The new infected added are the jockey, charger, and spitter. The jockey jumps on a survivor's back and can steer the survivor away. The charger plows through the survivors, grasping one in its giant arm and repeatedly pummels the into the ground. The charger can only perform its charge ability in a straight line, making it tricky to use effectively. The spitter spits acid on the ground, hurting any survivors that stand on it. Versus mode and Scavenge mode are amazing with the variety of Infected you can play as.
Like the original, Left 4 Dead 2 stresses teamwork. With the new special infected in the game, even if one person is not cooperating with the rest of the team, the entire team will suffer for it. When playing as the Infected, you will constantly see people who don't understand teamwork, making them easy pickings for you and your team.
Left 4 Dead 2 is simply the best co-op shooter to date. With the addition of all the new items, weapons, and special infected, it easily surpasses it's predecessor and offers many hours of enjoyable gameplay with your friends.