Persistent Upgrades

Persistent Upgrades, also known as "Perma-Perks", are unlockable upgrades that the player(s) can gain through unique methods. These upgrades only take effect and can be acquired on Green Run, Die Rise, and Buried (although only in their main modes; upgrades are absent from submaps such as Farm or Borough). The player can have multiple upgrades at once, and they carry over to different game sessions and maps. They can also easily be lost, usually if the player does not make use of the upgrade.

When an upgrade is obtained, a green haze (similar to picking up a Power-Up) appears near the player, and the player's character will say a line about it. Losing one will result in a faint eerie sound.

Persistent Upgrades can't be obtained nor will they be affected when playing in Local or LAN Party.

Faster Revive
The player can earn this persistent upgrade to revive faster by reviving downed allies seventeen times in one game. This effect can be stacked with Quick Revive. Reviving a downed player with it, without Quick Revive, will take 3 seconds to revive (same as having Quick Revive without the perma perk). If the player stacked both, it will only take 2 seconds.

To lose it, the player must try and fail to revive a downed person, even if said person is later revived. Even an accidental fail (such as being knocked out of the way) will cause the upgrade to be lost.

What seems to be the easiest way to aquire it is start a match of Tranzit and have a player stand in a lava pool near the edge at the bus depot. Have the player obtaining the upgrade stand near the edge and revive the player each time they go down, repeatedly until the upgrade is aquired. This can be repeated with all players in the match as the loss of the upgrade can is not associated with amount of downs.

More Headshot Damage
The player can earn increased headshot damage by getting an arbitrary amount of collateral headshots (multiple headshot kills with one bullet). In addition to increased headshot damage, shooting a zombie anywhere will make its head pop, although this effect is aesthetic. Sometimes the green flash will show in Survival on any of the survival maps, though the persistent upgrade will not be applied.

This seems the most noticeable with the M1911, where it originally would take three shots to the head on round one, would now be two.

To lose it, the player must kill twenty five to seventy five zombies in a row without a headshot.

Stronger Barriers
The player can earn stronger barriers to be built on windows by repairing seventy five barriers in one game. The barriers are partially made of steel and screwed in, so it will take more time for them to be taken down.

This upgrade will not take effect and cannot be earned before round ten. To know that the player has obtained it, they will hear some jackhammer and screwdriver sounds after each board has be built. Also, the boards will have more of a "fresh," newer appearance instead of the original, normal look.

To lose it, the player must fail to build a single barrier in a round.

Stronger Carpenter Barriers
The player can earn reinforced barriers for Carpenter to build by killing a zombie trying to come out of a barricade while the Carpenter is boarding the windows. The effect is separate from the stronger barricades above, and can be earned and lost without either affecting another.

To lose it, the player must fail to kill a zombie trying to break through a barrier during a Carpenter, regardless of if there are any.

200% Health
The player can earn 200% Health, with a down resulting after four hits instead of two. The effect stacks with Juggernog, allowing the player to have a maximum of 300% health. This upgrade is obtained when the player is downed without Quick Revive (thereby ending the game) three times.

This upgrade is automatically lost at the start of round fifteen, but player can still have it in this match until they are downed after round 15.

Insta-Kill Pro
The player can earn a subversion of Insta-Kill by not killing a single zombie during an Insta-Kill, twice in a row (though it will rarely be obtained from just one). The effect lasts fifteen seconds, is activated when an Insta-Kill is obtained and allows the player to simply walk into a zombie to kill it. Killing a zombie using it will only give fifty points.

To lose it, the player must be damaged by a zombie during the Insta-Kill (with the exception of a flaming zombie exploding).

Refund on Perks
The player can earn an upgrade to give one thousand points after buying a Perk-a-Cola. This upgrade is obtained by going prone each time you buy the perk approximately five to twenty-five times. The player must go prone after the perk appears on the screen and then has five seconds to go prone. This is not affected by Double Points.

To lose it, the player must not go prone in front of a Perk-a-Cola machine after buying it.

Mystery Box Upgrade
The player can earn an upgrade to decrease the chances of getting "bad" weapons from the Mystery Box. This upgrade is obtained when the player takes a random amount of weapons from the Mystery Box. They must keep taking whatever gun they earn. The player will see a glow and a teddy bear will appear on the box.

This upgrade cannot be earned after round ten.

This upgrade is automatically lost at the start of round ten. It can also be lost if the player refuses to take a certain amount of weapons in a row from the Mystery Box.

The teddy bear is not visible while the Mystery Box is rolling weapons except when a ballistic knife is fired into the bear.

PhD Flopper
The player can earn an upgrade to gain the effect of PhD Flopper. This upgrade is obtained when the player takes a certain amount of fall damage (enough to turn the screen red briefly) five to ten times. Unlike PhD Flopper, this upgrade does not protect against overcooked frag grenades.

This upgrade is only available on Buried.

To lose it, the player must take significant fall damage (around 80-90) by falling.

Half-off
The player can earn an upgrade to reduce all purchase costs by half during a Double Points Power-Up. If the player does not have enough money to purchase the item even with Half-off, it may take an even smaller amount. This upgrade is obtained when the player accumulates three thousand or more points during a Double Points Power-Up.

To lose it, the player must fail to spend at least one thousand points during the next Double Points.

Double Points
The player can earn an upgrade to give twice the points they would normally earn. This upgrade is obtained by only getting a random amount of headshots or melee kills only during a Double Points Power-Up.

To lose it, the player must kill a zombie with melee or a headshot at any time.

Tombstone
The player can earn an upgrade to retain all of their perks except Quick Revive after being downed and revived by Quick Revive or another teammate, being revived by the Pack-a-Punched Ballistic Knife will cause all perks to be lost but not the upgrade. This upgrade is obtained when the player buys four perks before round one ends.

The player can use points from the bank to purchase perks.

In a game with two or more players, the player will retain all of their perks except for their last obtained perk. Quick Revive will always be lost first, however.

To lose it, the player must go down three times in a row without any perks.

Bleeding Bullets
The player can earn an upgrade to bleed an extra three hundred points with each kill made using a sniper rifle. This upgrade is obtained when the player gets five to fifteen long range kills using any sniper rifle.

To lose it, the player must miss three shots in a row with a sniper rifle.

Double Pistol Points
The player can earn an upgrade to give double points from shots fired from a pistol. This upgrade is obtained when the player fires all rounds from a pistol without hitting a single zombie, then kills one to three zombies with melee.

To lose it, the player must kill one to ten zombies with melee or a pistol.

Ray Gun Off The Wall
The player can earn an upgrade to buy the Ray Gun off the wall for five hundred points (in place of the Olympia). This upgrade is obtained when the player buys the Olympia or ammo for it a few times.

The player can only obtain this upgrade if they are rank two or lower and they have two or fewer tally marks.

This upgrade is automatically lost between round twelve and fourteen.