Surviving the L4D Survival Pack

From the developers this week:

Survival Mode pits your team against never ending waves of infected. Sounds simple. Just trap the survivors in a small part of a map, unleash the hordes, and record the longest time. Survival Mode, which will be released next week, is actually a bit more than that.

Our goals for Survival Mode are to deliver a mode of play distinct from Campaign or Versus, have games that regularly last under ten minutes, and emphasize competition with team play through leaderboards.

Survival Mode draws on the planning and communication aspects of a successful Finale or Crescendo event, while taking it to another level. It rapidly hits a fever pitch that only a well coordinated team will be able to successfully survive. Everything from simply covering a reviving teammate, to making every shot count to minimize reloads becomes crucial in Survival Mode.

Given the importance of pacing in Survival Mode, we need to define as precisely as possible how the difficulty ramps up during the course of a round. We have numerous variables to work with: mob spawn frequency, special infected spawn frequency, number of each type of special infected, total number of special infected, tank spawn frequency, total number of tanks, and so on. We need all of these variables to work together to create a fairly smooth difficulty curve.

If the curve ramps up too sharply, we find that teams of all skill levels tend to hit a wall at the same time. There isn't enough variation in the times to separate great teams from average ones. If the curve is too flat, then average teams will have a good experience, but really good teams can grind on long enough to cross the line from having fun to just getting worn out.

It might seem that just gradually increasing spawn rates and numbers of infected will create a nice smooth curve, but it turns out to be much trickier than that. Each type of infected has its own spawn schedule, so even though the individual spawn curves may be designed to be fairly easy at a particular point in time, sometimes they overlap in just such a way that the players find themselves in a really bad situation far earlier than we intend.

For example, a tank will be much harder to fight if a mob of common infected spawns at the same time - and nearly impossible if three hunters also show up right at that moment. A similar situation can happen due to variables outside our control - a team may not dispatch a tank or mob quickly enough, causing subsequent waves to start arriving and piling on to an already difficult battle. It's also hard to anticipate when teams will need to make an ammo run or heal up, both of which can be extremely difficult only a few minutes into the round. In order to help visualize these overlap points and the collapse of each spawn curve, we graphed out the wave behavior of infected over the course of a survival round.


The last variable we added was the "lull" - a short interval of time during which nothing new will spawn. Each lull gets slightly longer as the round progresses, but that's no guarantee the team will actually see the lull - it just prevents new infected from spawning. It doesn't help with infected that are already in the arena. Killing mobs and tanks as quickly as possible is the best way to ensure that a team can take advantage of a lull to heal, resupply ammo, or just move to a better location with more supplies.

Given the extreme pace of Survival Mode, the number of zombies killed in a single round often outnumbers an entire campaign. Even optimizing towards using pistols to eliminate common hordes, ammunition usually becomes an issue at some point. As ammo piles provide a unique infinite resupply for players, they tend to be in relatively less defensible positions in the Survival arenas. This means making an all important ammo run is rarely a safe proposition and requires good teamwork and planning. Timing your resources correctly to be able to make a run when necessary can make or break a team. The perfect pipebomb or well placed molotov can mean the difference between a cakewalk and catastrophe.

The Hospital Elevator, for example, might seem like an easy Crescendo Event to conquer. Hit the elevator button and holdout until the doors open for a quick escape. In Survival Mode, however, the area begins locked down. Areas open as the hordes come in, breaking down the doors to reach the survivors. In each room there are additional caches of vital pills, pipes, and Molotovs. By moving from location to location, using up the plentiful supplies as needed, a team can maximize their time in a game where the elevator never arrives to offer escape. In other maps, items may be less plentiful and require careful planning on their usage. Managing one's inventory and resources works hand-in-hand with teamwork in Survival Mode.

Left 4 Dead Health Packs

Health packs in Left 4 Dead are one of the most powerful and mis-used items in the game. It is very important to understand how to maximize their potential. Health packs serve two purposes:

• Healing a survivor. This may seem obvious, but health packs in L4D only restore 80 percent of a survivor's available health. If you are at 50%, a health pack will give you 40 hit points to heal you to 90% (80% * 50% = 40%; 40% + 50% = 90%). If you are at 30%, a health pack will give you 56 hit points to restore you to 86% (80% * 70% = 56%; 56% + 30% = 86%). The lower your health, the more benefit you will get from a health pack. This also means you can never heal to more than 99 percent. If you're using a health pack on somebody (you or a teammate) isn't red, you are wasting health restoration points.
• Resetting the incap counter. Once a survivor has been incapped and helped back up twice, they start slowly bleeding out. Their screen turns black and white, and they will die on the next incap. The ONLY way to prevent death from three incaps is by taking a health pack. It restores their health and resets the incap counter.

That said, here are some good and bad times to use a health pack.

Bad times:

• Early in a level where you got brutalized by the horde and are at 40-99% health. You aren't moving that slow at this point, you don't need to waste the health pack. Save it for a better time.
• Right after you've taken pain pills. Pain pills temporarily restore all you health. Taking a health pack at this point wastes the pills.
• When your entire team is a similar health/damage level. If everybody on your team is at 20-30% health and moving kind of slow, taking a health pack by yourself will make you too fast. You'll tend to run ahead and get separated.
• Right before trying to mess with a witch. Even the best players in our clan can not take out the witch successfully 100% of the time. The witch's primary attack is an auto-incap and immediately zeros out the survivor's health. As long as the rest of the team is close enough to take the witch out pretty quickly after the intial attack, it often makes sense to send the weakest player in to piss her off.
  
• In Campaign mode on Expert: You should NEVER take a health pack until you've been incapped twice and your screen is black and white. Health packs NEVER appear on the level, only in safe rooms. They should only be used to reset incap counters or to heal before picking up a new pack.

Good times:

• When a survivor has been incapped twice and their screen is black and white. This should always be a priority. Having a dead survivor is almost always the worse of the alternatives. Reset their incap counter so that you have an extra gun, and an extra survivor to revive you when you get incapped.
• To pick up a new health pack. Never leave health packs unused. If you see a health pack on the level, and everybody is already holding a health pack, the player with the lowest health should heal, and then pick up the new health pack. Often times there will be health packs at the site of a big battle. It is usually better to use the health pack(s) AFTER the battle, than before.
• Once everybody is inside the safe room. On Versus, you get points for much health you have. Everybody should heal before closing the door to maximize your score. Don't stand too close to the door while survivors are healing though, because the Infected can still get you until the door closes.
• When you are the weakest link and speed matters. If you are the only survivor who has significant damage to the point where you are slowing down the party, and where the team would do well to progress quickly, then you should heal so that you can keep up. This typically means you are below 30 percent health, and you are in a wide open area. Because of how the horde spawn spots are set up, there are not too many places in L4D where speed is more important than saving health packs. So use them wisely.

Remember that the way we play L4D in Versus, both teams can hear each other the whole time. You basically have to announce that you're using a health pack so that your team mates don't run off ahead. Once you've announced it, you've basically advertised to the Infected that your team has spent one of its four precious health packs (and are now weaker for it), and that your team will be sitting in one spot for a while waiting for you to heal (and be vulnerable to easy Infected attacks).

Left 4 Dead n00b Q&A

Q: It's pretty easy to pounce survivors, why do you say the Hunter is the hardest to learn?
A: The Hunter doesn't do any damage from the pounce and does damage relatively slowly. If the Hunter is knocked off or killed quickly, the pounce basically doesn't hurt. An effective Hunter finds isolated victims where he can spend some time clawing at them after the pounce.

Q: The Boomer seems clumsy, how do I use him effectively?
A: The Boomer is a huge target and is easy to kill, so it's important to spawn someplace where you can barf on the survivors as soon as you reveal yourself. Good examples are in the next room, around a corner, or on a rooftop. Bad examples are way out in front, down a long hallway, or way behind the survivors where you have to run for a long exposed stretch to reach them.

Q: Why does it take so long for the Infected to respawn?
A: This helps to balance the teams and encourages the Infected to be smarter about their attacks. All of the Infected (except for the Tank) can recharge their attacks if they aren't killed. The Hunter can actually recharge health as well.

As an Infected, you should go into hiding after your attack so that you can recharge and attack again. As a Survivor, you should exploit the long respawn time and cover as much ground as possible after you kill the special Infected.

Q: I'm not sure how the smoker works. Everytime I tongue someone it never seems to drag them and then it gives away my position and I'm dead.
A: Wait until your smoker reticle turns red before attacking. It's very unlikely that you'll grab somebody unless your targeting reticle is red. If you drag them over a rock or through a big tree, it will break your tongue. Doorways are usually ok, if you have a clear shot and don't get them caught on the doorjam. A good survivor team will break the tongue before you can do damage. In general, the smoker does best at pulling a survivor back or from the rooftops...it's much harder to attack survivors from in front. No damage is done until you get them all the dragged to you or they're hanging. A long drag backwards is SUPER useful, even if you don't do any damage. That usually separates the survivors or makes them backtrack.

Q: Once you've pounced with a Hunter or dragged somebody in with the Smoker, do you have to use LT to secondary attack?
A: No, you will automatically damage them when they're dragged in or pounced. You can basically go get a beer at this point.

Q: What is the best way to knock off a Hunter or Smoker?
A: LT (melee) is VERY versatile. It will knock off a Hunter, block a Hunter from pouncing, break a Smoker's tongue, block a Smoker's tongue from locking on, or push a Boomer far enough way to kill without getting barfed on. LT does not do any damage to Survivors, so it's a safe way to save your teammate without hurting them.

Q: If pounced by Hunter or dragged by a Smoker, is there anything you can do?
A: Once you're pounced, you're helpless, there's nothing you can do. Which is why, above all else, you can't be by yourself.

Q: What can I do to get better as a Survivor?
A: I'd recommend playing through the No Mercy and Blood Harvest (1st and 4th) campaigns on your own a couple of times. It's the exact same layout as versus, so you'll learn the maps. The other two campaigns are beign released as versus maps in the Springtime. You can just play on easy for a while, you mainly want to know the maps inside and out. Spend some time exploring so you know which rooms have stuff in them and which are just death traps. Most of the rooms are death traps that you don't want to wander into, but you want to pay special attention to the ones that have health cabinets on the wall, or ones that you find advanced weapons in. The cabinets are always there, but the AI director will decide whether to spawn pills or health packs. The tables for advanced weapons are always there, but the weapons aren't always there. Second pistols, molotovs and pipe bombs spawn at the AI director's discretion, they may or may not be there again on your next play through.

Left 4 Dead Basic Survivor Tips

Above all else, STAY TOGETHER. Zombies love love love to pick off the stragglers. If you must leave the group for some stupid reason, make sure you have a buddy with you.

Talk. Lots. L4D forces team play, much more so than any other game I've ever seen. As survivors, you are easy prey and easy to find, so talk to make sure everybody leverages what advantages you have. This includes telling your team mates about weapon locations, coordinating who uses health packs, and notifying each other where special infected are located.

Call for help. And keep doing it. If you get pounced or tongued, make sure your teammates know. They may be busy and can't get to you right away, but don't give up on telling them you've been caught. There's a lot of chatter, you want to make sure you get heard. A dead or incapped teammate is WAY worse than an annoying chatterbox.

Distribute your weapons. A balanced loadout has two survivors with shotguns and two survivors with machine guns (SMG or AR). If your team is 1337, the ideal advanced loadout is two auto-shotguns, one AR, and one hunting rifle. But I don't think anybody is that good yet.