Crash Course

Crash Course is the first DLC campaign for Left 4 Dead. It is free on the PC, but costs 560 Microsoft Points for the Xbox 360 version. It was released on September 29th. According to Valve, it is meant to bridge the gap between No Mercy and Death Toll.

Crash Course begins shortly after the events of No Mercy, with the Survivors starting out by the crashed remains of the helicopter that had rescued them. The helicopter pilot became Infected, and was killed by Zoey, causing the helicopter to crash into the ground. A whole selection of new audio has been recorded especially for this campaign, whilst still retaining the wit and patter that the game currently possesses. The density of the Survivors' dialogue is also noticeably higher.

The new campaign is much shorter than the others, which is a deliberate decision on the part of Valve. This was decided so that players could experience a much shorter, and much more intense game in Versus mode. Crash Course consists only of two chapters, which according to Valve, is a perfect length for a quicker, more decisive Versus match.

The two levels have been packed with everything players would find in a normal campaign. This can result in players finding tier 2 weapons almost straight away. However, the campaign will be faster-paced, and the Survivors could be attacked by the horde almost immediately from the very beginning. The levels have also been designed to give Special Infected plenty of advantages, once they learn the terrain.

Each of the two chapters (The Alleys and The Truck Depot) have their own major finale event as well, with the first one taking place on a blocked bridge. In order to clear the blockage of abandoned cars, the Survivors need to activate an artillery cannon to blow the vehicles out of the way. The Infected then swarm in on the area, which consists of a wide open space and a large house. The bridge itself is littered with cars and obstacles.

Fans of Left 4 Dead's safe room graffiti will be pleased to know that it returns in Crash Course.

The finale of Crash Course sees the Survivors reach a garage, where a bus is waiting at the top of a vehicle elevator, just out of reach. In what looks to be a homage to the Dawn of the Dead remake, the bus is armor-plated and is designed to take the Survivors through to safety and away from the Infected. Unfortunately, players must first get the bus down, and that requires use of a generator located in the parking lot outside.

The generator, unlike usual finales and Crescendo Event, takes time to activate, with players having to wait while the power charges up. Also unlike other finales, the generator sometimes fails, requiring a second activation. Once it's powered, the bus lowers and the horde arrives. This finale is particularly difficult for the Survivors because the Infected can attack from virtually every direction. After several long minutes of sustained horde attack, all of the power goes out.

Players are now stuck in the dark, surrounded by the Infected, and need to fight their way back to the generator in order to switch it on again, stuck in the open and having to slowly wait for the power to return. Of course, a Tank will make his appearance as with every finale. Once the bus is lowered, the Survivors enter in the back, and they escape.

Crash Course is intended to allow the full experience in Versus mode in just 30 minutes. The map will also include a recharge timer for the Infected and new item spawn behavior.

Trivia

 * On the campaign poster, Louis and Francis are both dual wielding with a primary weapon and a pistol. However, this cannot be performed in actual gameplay.
 * Like in other Campaign posters, Bill and Louis are holding scoped MP5 submachine guns, which are not included in-game.
 * The body of the pilot can be found right behind you as soon as you start the first chapter.
 * The location of alarmed cars spawn differently every playthrough.
 * The rescue bus is fortified like the bus in the 2004 remake of Dawn of the Dead, including the cow-catcher's paint job.
 * In the safe-room, there is a map of the United States on the wall showing key regions "X"d out. The only two areas without an "X" are in Pennsylvania, where Left 4 Dead takes place, and New Orleans, where Left 4 Dead 2 takes place.
 * If you stand at or near the blockade on the bridge, and someone fires the howitzer, you will only become incapacitated, usually with enough time to be revived.; If you are touching the blockade in the middle, however you will be incapacitated in the fire, which usually results in death before anyone can make their way over to you. However, if you stand right in front of the barrel of the howitzer, you don't block the shell being fired; it passes through you and you take no damage.
 * Bill has no new lines. When activating the generator he reuses "Watch my back" and "I'm getting too old for this horseshit." He says very little throughout the campaign, although he occasionally says "Get to the chopper!" when telling people to get on the bus.
 * If a Survivor (except for Bill) walks over to the pilot against the wall, they will usually say something about him.
 * If the subtitles are on, one will notice that all Crash Course sensitive lines are Francis' dark gray color, regardless of who speaks.
 * Crash Course's finale is the only finale without someone to pilot the rescue vehicle, as it can clearly be seen that the driver's seat is empty. This is also the only finale with no radio to tell you to prepare (However, there is a corpse with an unusable hand held radio near the truck); this mechanic is replaced with one Survivor having to hold down the interaction button to activate the lift.
 * Crash Course is the first campaign in Left 4 Dead to occasionally have tier 2 spawn points featuring only one or two of the usual three weapons.
 * During the finale when the rescue vehicle is being lowered, if you're standing underneath the lift you'll be incapacitated and then die a couple of seconds later.
 * Many of the achievements are glitched. Even though one can do what is necessary to unlock them, they can remain locked. While some, like Smash Hit, may unlock when you've done something completely opposite to it's task - in case of Smash Hit, you may lose the game and get the achievement. The best way to unlock them is to play Versus on a local server. This is achieved by random, but you will know that you are on one if the game starts counting down (Starting Game in 5 Seconds...) On the local server, all achievements on Crash Course are unlockable.
 * In the poster, the Helicopter looks like a military issued Apache or Blackhawk when in-game it's a civilian chopper. As well as this, it is depicted as being crashed on it's front, when the actually helicopter crashed on its side.