Creepy Crawlers

Zombies- there are three types; runners, walkers, and crawlers.  Runners are fast and loud, newly dead and screaming randomly.  Walkers are slow and quiet, corpses that have started to decay and typically not making any sound.  Crawlers are even slower, bodies that have decayed almost all the way and aren't silent but aren't loud either.
Spores- spores are like giant spiders with red bumps on their back.  Their attack is like the Head Crabs from Half-Life; they jump on a person's head and suck the brain dry.  After that, they control the corpse.

And that's literally it.