According to Rusty over at Laughing Squid, Zombiez isn't really gory or anything, and the zombie theme is really only present in the menu names and some decor choices. So if you're looking for a flesh-and-brains sandwich (with a side of bath salts), you'll need to shop elsewhere.
Although Rusty says the food is quite good, so maybe it's worth walking your dead self over there for a bite if you live in the area.
-Aaron Sagers