Tactical evaluation, Strategic threat evaluation.Crawlers: Post-human infected who....walk. Badly, but so it goes. They make verbal noises. Some are more aggressive than others, but it is uncertain as to whether that is related to their former personalities, physiques or the unknown processes that keep them moving.
Power: Strong human
Scary: Unsettling
Threat scenario: Large numbers, confined spaces. Otherwise, easily outmaneuvered.
Spitters: Post-human infected who mutated into walking guns. They can spit high-velocity, infestive, acid/enzyme globs that can kill, maim and possibly Turn on impact.
Power: Strong human, strong ranged attack.
Scary:
Dangerous 
Threat scenario: Open areas with no cover. Difficult to engage hand-to-hand; use ambush or projectile weapons.
Basilisk: Post-human infected with some intelligence that can use a poorly-understood mental paralysis initiated by eye-contact to trap prey. They are known to be clever tactically and use deception to force prey to meet their eyes.
Power: average human; silent ambush ranged-attack.
Threat scenario: Ambush, anywhere they aren't expected or where normal humans are expected. Danger is extreme for lone individuals. Plus, this ability seems to be specifically evolved or more probably designed against humans. Design implies an intelligent, non-human purpose.
Berzerker/Raver: Zombie with speed, learning intelligence, and apparent hatred. This type is probably the more independent.
Power: Strong human, Olympic sprint speed, strong melee attack possibly with improvised hand weapons.
Scary: MMA Psychotic Dangerous
Threat scenario: Within 40m, if single. In packs ("riot squads"), within 40m*zombie count.
Advice:Best to engage from behind bars, 7' tall sheer fortifications, or from highly mobile vehicles using large-calibre, rapid-fire weaponry. In hand-to-hand (not recommended), metal-hafted barbed spears with cross-hafts can be used to impale ravers long enough to allow for a crushing head blow from a club, mace or weighted flail. Setting such spears to receive their charge will help prevent them from overbearing you, but only if your spear has a cross-guard to prevent them from just working their way down the shaft to arms length. Be aware that its companions may change tactics if spears prove effective, possibly flanking you or jumping over your spears to come at you from behind.
Howlers/Banshees: A crawler zombie with a secret weapon. At close range, it emits a low-frequency moan that affects the human brain causing vertigo, pain and unconsciousness.
Power: Strong human; undodgable hidden attack
Scary: Freaky deadly
, if not aware of the attack potential or if not armed with projectile weapons.
Threat scenario: Ambush, either from standard tactics in an urban center or from a 2nd or 3rd wave of crawlers.
Advice: Howlers will howl; listen for them. If you know they are out there, take pains to ensure at least 10' of stand off during an engagement with crawlers. Consider any building an extreme-threat zone, as the close-quarters will prevent detection until you are already stunned. Howlers do not need line-of-sight in this type of environment.
Hunters: Possibly a focused, evolved form of berserker zombie. Fast, flexible and dedicated to a single human target, they have all the hallmarks of a designed weapon for assassination. This zombie type implies a central intelligence that is aware of human high-value targets.
Power: MMA Ninja Terminator
Scary: See Power above.
Terrifying, if you know they exist and they know you exist.
Threat scenario: Always a terrifying threat. Solid fortifications allowing for constant surveillance of wide stand-off zones will make it difficult for individual hunters to infiltrate. While reputed to work alone, their appearance would allow them to blend with the in-crowd, allowing for a sudden ambush strike once within the 40m danger zone.
Advice: Detect and hunt them first. Treat them with the same respect as a berserker: projectile weapons, spears, armor. You MUST find a secure place to sleep quickly, as hunters are adept as wearing down human prey with constant "teasing" and probing attacks. Trees are a poor defense, as hunters climb quickly and have a verified 5m vertical leap. Concrete-based skyscrapers are ideal, as the 2nd floor is often 6m or better from the street. Numbers are your advantage; sleep in 3 to 4 shifts.
Mercy: Possibly a sub-type of hunter zombie, a mercy is known to be fast and flexible. It shows the focus of a hunter, but with a larger portion of patience. It seems to leverage the hunter's predilection for wearing down its prey. In terminal mode, it shows the same focus, delivering a single, targeted bite designed to allow the victim to bleed out, while seeming to "comfort" the dying person.
Power: Strong human, adaptable.
Scary: Unsettling
, but typically less of a threat that a crawler.
Threat scenario: If alone and unarmed.
Advice: Don't be alone and unarmed. Pace yourself and keep moving to keep the mercy at bay. Find secure shelter.
Future: If zombies are being evolved, we can expect more Mercy-Hunter-Banshee-Spitter hybrids that combine speed and agility with special abilities. The forces involved may possibly evolve a Diplomat zombie to directly engage humans.
