Difficulty

Each difficulty has different zombie spawn rates and rewards. [Plz add to this, not accurate so you're welcome to edit] 

Easy

Reward:100$ - 175$

Infected Chance:20%

Start Infects:2 - 4

Medium

Reward:200$ - 275$

Infected Chance: 30%

Start Infects: 4 - 6

Hard

Reward:300$ - 375$

Infected Chance: 40%

Start Infects: 6 - 8

EXTREME

Reward:400$ - 500$

Infected Chance: 50%

Start Infects: 8 -10

Special Cases

King Cake:EXTREME (Always)

Reward:Varies

CTF:EXTREME (Always)

Infected Chance: 60%

Start Infects:8-10

Reward:470$ - 500$

SBF, FFA, and MMA:Unknown (Always)

Reward:0$ -100$

Mixed Gamemodes

Obby

This gamemode was exclusive to the Halloween Obby map, which was in the Halloween 2014 event. In this gamemode, players will have to complete an obstacle course to achieve a reward.

Bunny

This gamemode is exclusive to the OpenFields Map, which is in the Easter 2015 event. In this gamemode, players and win 1st, 2nd, or 3rd place in a bunny race. Reward depends on place. You will also get some cash.

1st place: 3 bunny points

2nd place: 2 bunny points

3rd place: 1 bunny point

Trivia

The smaller the server, the more likely you will become an infected.

The harder the difficulty, the more likely players will spawn as special infected.

Place hasn't decreased the spawn rate of smokers ever since the Winter Games so spawning as a smoker is likely.

Crawlers spawn more in layby no matter what difficulty it is

Your percentage on being a zombie lowers down during every round when you're a zombie, but increases when being a survivor.