The movie shifts tones a few times during its run-time. The first section of the movie is surprisingly grounded and measured, built around the sense of alienation and melancholy so many of us remember from grade school. We're introduced fairly quickly to the lead character's "power", to see and speak with the dead. For the record, this feels more reminiscent of Frighteners than Sixth Sense, which is probably best. The movie also does a admirable job of selling this as a curse rather than a blessing: not being able to turn off his visions makes them difficult to ignore and impossible to hide.
The movie's tone changes abruptly when the dead literally start rising. This section feels something like a deconstructed zombie movie and is mostly played for laughs. I enjoyed these sequences well enough, but I will admit to feeling a tad let down by the quick pacing and "no one's going to get hurt" vibe. In addition, it bothers me that the constant parade of ghosts who were always around in the first section just seemed to vanish halfway through. I understand they were trying to keep the movie focused, but it felt like an awfully large omission.
Fortunately, just when I was getting ready to write the movie off as merely "pretty good", the tone abruptly shifted again, leading to a finale that was almost impossibly beautiful, while simultaneously delivering some genuine horror. Not too much, mind you, but the final confrontation wasn't strictly kids' stuff.
ParaNorman's a great movie in a surprisingly large sub-genre of family-friendly horror/comedies. This, Coraline, and Monster House all play together nicely and build off a larger tradition of all-ages dark movies that include classics like The Secret of Nimh, Gremlins, Ghostbusters, and most of Tim Burton's early work. ParaNorman could have skewed a little darker and risen to stand with the best of the pack, but as it is it was still a great picture with fantastic animation, good writing and characters, and it was a lot of fun.