Common/Enraged Infected
You will be given a set amount of generic infected depending on the level you play on, you may place them through out the map as you see fit, just be careful not to bunch too many into one spot, try spreading them out to make the map more difficult. Every infected MUST USE THESE.
Tier 1 - Each infected may use an unlimited amount of these, but only one per infected player. You may all be slashers if you wish, but it is advised to be different infected. Once the infected is killed, they must wait a respective three turns (three posts by the person who died) before becoming a new Infected, though they may freely play as the Common/Enraged Infected.
Slasher
Leaper
Lurker
Infector
Divider
Infected Dog
Tier 2 - Each infected may use an unlimited amount of these, but only one per infected player. Only one Tier 2 Infected may be on the field. Once the infected is killed, they must wait a respective six turns (six posts by the person who died) before becoming a new Tier 2 Infected, though they may freely play as the Common/Enraged Infected or a Tier 1 Infected once three turns have gone by.
Boomer
Pregnant/Swarns
Guardian
Pouncer
Charger
Snatcher
Tier 3 - These are the boss infected, each of them are extremely powerful and can rip through the survivors with ease, but a coordinated group can take these big boys down, unless you are more coordinated that is. They each have their own strengths and weaknesses, serving better for certain environments or situations, but determining that is your own call. Only one of these creatures may be on the field at once, and may be spawned at any moment during the campaign. Each level has a limit to the amount of Tier 3 infected allowed, some maps only allow one boss infected to be spawned through out the entire level, while some others allow two even three. Once one these bad boys are down, you must wait at least nine turns (nine posts by the person who died) before spawning a new boss infected, six turns for a Tier 2 infects, three turns for a Tier 1 Infected, and they may freely play as the Common/Enraged infected while waiting.
Alpha-Pouncer
Gore-Hound
Juggernaut
Brute
Berserker