I really liked this story. It really attacked from two fronts: the horror of the monsters themselves, and the horror of life's inertia. The monsters were well portrayed, asequately strange and the scenes where the boys were running from them were well paced and tense.
The second (perhaps, larger) horror was basically that of the failed "coming-of-age" story. Normally, the story is one of a young man in a small town who grows, develops, changes and ultimately moves on to bigger and better things. In this case, our lead actually regressed - less successful with women, less brave, less potential etc. - rather than growing. In many ways, that trap is one we all can fall into. Suddenly, twenty years are gone and all those childhood dreams are now not only impossible to reach - but, worse, we don't feel they are even worth reaching for anymore.