We've been playing a loooooooot of Left 4 Dead. There's been a lot of tips, tricks and other weird stuff we've learnt either through our own trial and error or just through other players telling us.
So we've compiled it all here. This WILL make you a better Versus player because there will be at least one thing on this list you can take away and use in your matches. Read away and happy hunting!
GENERAL ADVICE
Purple outlines means puked players - go after the others!
The golden rule as ANY infected is - let the Boomer go first. If this means waiting a couple of seconds for the Boomer to spawn, so be it. When the survivors are puked, they can't see those who have been pounced or constricted. The only tell-tale visual sign they have is when they look at their team-mates directly so their gamertag appears, and seeing it either low on the ground (pounced) or jiggle around (constricted). The horde also makes it harder for them to move and save other survivors anyway. So let Boomers go first, then go after those who haven't been puked (the green outlines) as the puked players (the purple outlines) will struggle to do anything about it.
If some players have quit, leaving bots on the survivors team, remember you just need to kill the human players in order to win. If there's just one human player, killing him will win the match, even if the three other bots are alive.
The advanced weapons will spawn in the same area for both teams. If you're playing as the Infected, keep an eye on where the survivors get the advanced weapons from, and make sure you take the team to the same area when it's your turn.
If the petrol station on No Mercy 3 is blown up, the explosion will also kill ANY Infected and immediately incap any nearby Survivors. As a smoker, hang around near the petrol station and pull Survivors in towards it. Hopefully, the other Survivors will panic and shoot at you rather than meleeing you off. Once the petrol station has exploded, the hunter can also set himself on fire in the wreckage.
When a player is incapped for the third time, he'll immediately die. Keep a mental note of who has been incapped and focus on that player. Unless a med kit is used to restore his health (and thus, reset his incap count to zero), he should be the primary target of the infected.
SURVIVORS
This door in No Mercy 3 can be meleed through
On No Mercy 3, you can melee through the door to avoid activating a horde. Instead of pressing the button on the lift, hug the wall in front of you (under the ledge) and run all the way to the left. You'll notice a huge metallic door, that looks like a garage door. Melee it for 15 seconds or so and it'll break down, saving you a horde and several tough ambush points to fight through.
You can use a 'double melee glitch' to speed things up here, and for defending yourself in general. Melee, switch weapon, melee, switch weapon, melee. Keep repeating to speed up your melee attacks.
Your green outline only appears if you're running around, firing your gun and you have your torch on. If you turn your torch off and walk around crouched down, your outline won't appear at all, so you'll be invisible to any spawned infected.
You can use the petrol station in No Mercy 3 to your advantage. The explosion will send debris over to the left, that lets you climb up to the hidden rooms in the apartment block. Depending on what has spawned, you'll find pills, molotovs, pipebombs, health packs or advanced weapons here.
On No Mercy 4, it's often worth taking a pipebomb or gas canister into the lift with you, as the explosion from either of these will move the generator if the Infected have tried blocking the lift. The main areas to check for pipebombs are - the room to the right of the safehouse, all the rooms in the corridor leading to the reception area and the lift corridor itself.
Healing yourself makes NO difference to the health bonus in Versus. The health bonus starts at a set point total and decreases as you get hit. Healing does not replenish it. Therefore, you shouldn't waste time healing if you're only doing so for points, as it won't make a difference.
It's better to have team-mates heal each other than for a player to heal himself. The reason is that the player being healed can still fire his gun when another team-mates is healing him, so he can defend himself and the healer.
You can replenish ammo just by picking up an advanced weapon. If you pick up an advanced weapon and then burn through ammo because of a horde or a special infected attack, just pick up the same gun again to max out the ammo again.
Just a cute bonus, you can shoot your pistol and melee while the helicopter swoops by in No Mercy. Oddly, this doesn't work for Blood Harvest.
HUNTER
Set yourself on fire as a Hunter before pouncing
If you can, set yourself on fire as a Hunter. It makes no difference to your melee damage but your pounce damage will go through the roof. As a rough approximation, your pounce damage will triple while you're on fire.
As a Hunter, clawing is often way more effective than pouncing. It does 10 hit points of damage and in a horde, will often be shrugged off as a standard zombie swipe (especially if that player has been puked on). Try to claw players on yellow, always claw players on red health.
Straight after a player has been revived, three melee swipes from a Hunter will put him back down again.
Pouncing from height as a hunter does 9 damage before you even start clawing. Practice leaping from the No Mercy 1 rooftops onto the survivors in the alleyway below.
If a survivor has backed himself into a corner and started meleeing, the best way to attack him as a hunter is to pounce at the wall directly above him. You'll crash into the wall then fall on his head (which avoids the melee range), which leads into the pounce animation.
BOOMER
Don't shoot boomers near alarmed cars or witches!
If a Boomer explodes, the explosion will 'activate' anything near by. In other words, stand by a witch or alarmed car when you spawn as a Boomer and at least one panicky survivor will shoot at you. When you explode, you'll set the witch or the car off.
If you have spawned as a Boomer and see someone who has been pounced away from the group, stand by him but don't puke. Someone will have to come back for him - block the survivor's view of the hunter as he comes back so he can't shoot and if he gets close enough to melee, you can puke him and the guy on the ground in one go.
SMOKER
One of the few instant KO spots with the smoker
There are three notorious instant kill spots with the Smoker. The well known one is the 'satellite' kill on No Mercy 5. If you spawn as a Smoker, run to the helipad and climb the nearby building with the satellite, moving over to the left. If you constrict and drag any survivor climbing the ladder to get outside, you'll drag him off the building and the fall will kill him.
There's a rope bridge crossing a canyon in Blood Harvest 1. Spawn as a Smoker and run across the bridge, then move to the right across the cliff. Turn back to face the survivors and if anyone approaches the cliffside (which shouldn't happen but for some reason, lots of people do), you can drag them down into the canyon for an instant KO.
In Blood Harvest 2, the survivors have to smash the windows to climb onto the walkway after leaving the safe room. Spawn as a Smoker down below and drag them off the walkway into the middle of the room (so there are no barriers in the way). Again, an instant death.
TANK
Stay in green health if you can, to outrun the tank
As a Tank, prioritise red health survivors, as they'll be running the slowest. After they have been incapped, target yellow health survivors. Try not to chase after green health survivors, as they can outrun you. And never beat down on an incapped survivor, as it takes far too long to kill them.
Discretion is sometimes better as a Tank. A team of four players armed with auto shotguns can kill a tank in less than two seconds. Make your presence known (make sure the team spot you) and then hide to throw rocks from distance. Your presence will impede their progress but also, your distraction will make it easier for the other Infected to do some damage.
To keep control of a Tank, all you need to do is connect with a rock, so don't panic and charge in if your control is dipping low.
The most effective way to use a Tank is to slap cars around. If any moving car touches a survivor, it's an instant incap. It's also the perfect way to deal with green health survivors, as you won't be able to catch them via normal means.
The Tank can only break down the safehouse door at the start, not the final safehouse door. Even so, the Tank can get lucky. Stand next to a safehouse door and throw a rock and the animation carries the tank through the door to throw the rock, before the animation carries him back out again. You can use this trick to catch unsuspecting survivors who tend to stand fairly near the safehouse door once they're inside.
Fighting against a Tank is much easier if your health is green, as this enables you to outrun a tank. Always take pills to get your running speed up or heal up if you're on red/yellow health.