Continuing the Left 4 Dead tutorial series, we discuss the merits of the special infected team.
The special infected team has a single mission - incapacitate or kill all survivors as quickly as possible. Work together as a team, coordinating spawn times and placement. At times, you might be better off waiting for a great setup spot, while others you might be using your special infected to simply slow or halt the forward progress of the survivors until your fellow undead respawn. By stopping survivor progression you also increase the chance of more naturally occuring Hordes. A team that doesn't move forward will slowly wear down.
Playing as:
Boomer: The Boomer is as noisy as a train, but has the ability to bring the progress of the survivors to a halt and to create chaos.
Your main mission is to hit as many survivors as possible (preferably all) with the Horde-summoning bile, and to do that you need to get as closely as possible without alerting them to your presence. Use spawn mode to make this happen! You can spawn in surprisingly close, usually just a few steps away - but you must be out of the line of sight. Try going around a corner, just out of sight of your opponents.
Now, it's not enough to hit all four survivors. Covering them in bile in a closed room or an easily defended hallway will only result in a slight pause in survivor progress as a smart team will simply crouch in a defensive formation and mow down the incoming onslaught. Look for open areas, or places where there are more than two possible points of undead entry. Pop out in a hallway junction or from behind the tractor in the field (Blood Harvest) for maximum hilarity. But for the love of god, get in close because your bile projectile doesn't reach too far.
In addition to corners and lone cover objects, another popular point of entry for the Boomer is from the rooftops. Drop down in the midst of the group and let her rip!
Hang out atop ladders and spit bile at the team below, such as the ladder to the streets from the sewers and the ladder to the hospital rooftop in No Mercy (thanks Kal)
So you've got a good idea of where to spawn... but the key is when. Standing around in your sneaky spot sounding like a foghorn will only get you shot and send you back into the spawn queue. Wait until the last possible second - just before they get too close for you to spawn - and then pop into existence. If you time it right, you'll catch them completely off guard.
Other possible good Boomer spawn times are during Tanks, naturally occurring Horde swarms, or when the survivors are otherwise occupied with something else. Boomers set up opportunities for other special infected, so DON'T WASTE IT!
Smoker: This guy has really limited opportunities, but is potentially a great team splitter if you bide your time. The worst thing you can do is spawn in and try to drag away a team member on level ground while nothing especially devastating is happening to the survivors. You'll get taken out very quickly.
The most effective place to spawn in as a Smoker is above or below the survivors - whichever place is most difficult to reach. Some good examples include pulling someone off the Lift rooftop in No Mercy and yanking people out of windows in the Blood Harvest finale.
Like the Boomer, the Smoker, because of his loud hacking cough, is an aural beacon for the attention of the opponents, and coupled with his distinctive shape and accompanying cloud of smoke may as well be wearing a neon sign that says SHOOT ME! Don't spawn in vulnerable locations. Rooftops, corners, and behind objects are most effective. And make damned sure that everyone else is occupied before you try to reel someone in.
It's important to note that you can deal some really quick damage if you can drag a player into a nearby fence or other impassable obstacle, because whenever dragging progress stops, the hurtin' begins! In the end, however, nothing beats dragging a player away from the group because separating the players is the name of the game.
Tank: If you spawn as a Tank, you have a couple of jobs and the first is to incapacitate as many players as you can. Try to "steer" your chosen prey into as many doorway frames and obstacles as possible, so that you can quickly close in on them. Stick with dealing damage to one player at a time because as soon as they are down they are reduced to pistol fire only, and to get the player back up another survivor is going to have to spend several seconds in a vulnerable "reviving" sequence.
The second task as a tank is to break up the team. Do this by knocking players down to lower levels or throwing cars. In fact, if you have cars, you can probably take care of the entire team in a few moments. But those are the only things you should throw! Don't waste your time digging up rocks to throw. Get in there and use your mitts.
One of the biggest challenges with the Tank is actually getting to the team with any element of surprise intact whatsoever. Being that you're a tank-like character, you cause the ground to rumble when you run. Heck, you even get your own intro-tune. Use cover as you approach to shield yourself from the inevitable barrage of bullets that are coming your way. As a special infected, you can see an outline of the survivors through the walls, so use that to your advantage so that you don't initially approach them head-on.
Hunter: Unlike the other special infected, you don't have your own theme music or signature sound - unless you crouch. Use this to your advantage in a couple of ways. If a team is not checking "their six", you can usually run right behind the stragglers, crouch at the last possible moment, and then make your move. But if you pounce about the level screaming, you're sure to draw your share of fire.
However, sometimes using your crouching growl or leaping screech can be a good thing! If you see the outline of a nearby Boomer setting up, crouch down out of sight and let out a few yelps. Not only is it sure to cover up the bellowing belches of the Boomer, but it's likely to turn a few heads your way as well, giving your team mate a better chance.
Hunters have the distinctive capability of instantly incapacitating a survivor, so look for those separated from the team. Keep an eye on Smokers and other Hunters to know when a survivor is coming to help his fellow man - then take him down. Team up with another Hunter to quickly take half of the opposing team out of the picture. The least effective approach is to bound towards a healthy and undistracted group. If you're trying to slow them down, even just hiding out of sight and growling is likely to be more effective.
A unique attribute of the Hunter is that more damage points are awarded for longer leaps. Jump from the roof of a building or bound off a wall for a hard-hitting first shot. Looking up quickly before you leap will cause you to soar high into the air.