Not a comedy... despite trailer

So, while this was more or less a solidly structured and acted movie, it sure as heck wasn't what I was expecting. The trailer makes it seem like a school-centered "Shaun of the Dead," with jokes and a dry British sense of humor.

Yeah, nope. This isn't a comedy, and it isn't trying to be. This is a movie that takes itself very seriously, and it's almost more like some kind of weird, zombie "Lord of the Flies" in a way. If you take out the humor, it kinda starts out like "Shaun of the Dead" and ends more like "Hot Fuzz." So, if you're looking for something light-hearted, find something else.
Basic plot:

The main kid, Lee Keegan, starts the movie with a prank that gets him suspended. But his dad isn't mad when he picks him up (unusually fast.) That's because his dad was picking him up for a different reason- there's a pandemic and panic spreading across the country. Lee eventually returns to the school for safety, but finds that the local community has begun operating as its own state, in a way. This leads into a clash with the survivors at the school.