Yes and no. This story is what I like to call 80's PG (not quite PG thirteen, but before they had that rating) it's very much in the vein of Goonies, Monster Squad, ET, etc. If you’re comfortable letting your children watch those kinds of movies, you would probably be ok with it.
There is some mild language, just like in ET and The Goonies. It you find the words “ass,” “dickweed,” or “boobies" particularly offensive, you may have an issue with the book. But that’s about as colorful as the language gets.
There are zombies, but never any scenes of them eating people. Any zombie attacks (zombies biting humans ) are shown off screen (off panel, in this case). The kids use blunt objects, firecrackers, model rockets, and the like to defend themselves against the zombie threat. There are no scenes of children using firearms.
The zombies themselves may be frightening to some younger readers. I have included some sample pages to give you an idea how the zombies are visually represented. In this universe, when you become a zombie your skin turns grey and your blood becomes a soupy green, so it’s not particularly bloody in the traditional sense (granted the interior of the book is black and white grayscale).