There are 2 types of zombies in No Zombies Allowed. There are regular zombies which basically look just like all the different survivor types just zombified, and there are bombies. They look just like any other zombie except they are red and there is puffs of smoke eminating from them. When you tap on a bombie zombie, you guessed it, they explode taking out any zombie around it also. Bombie zombies are your best friends on supply runs. They will clear half the field when you're lucky enough to get one.
There are various types of "special" zombie kills you can go for:
- Long range: Kill a zombie when it's way off to the side and hasn't approached the vehicle yet
- One-shot: Kill a zombie in one shot. Only possible with the Sniper Rifle (every hit), the Chainsaw (if very close), or occasionally the Shotgun at very close range.
- Double Kill: Kill 2 zombies in one shot. Most common with the Shotgun or Chainsaw.
- Triple Kill: Same as above, but 3.
- Mega Kill: Same as above, but 4 or more.
Presumably, these give you more bonus supplies/coins but I haven't quite worked out a formula around it yet.