Adorkable: Napoleon is a dorky highschooler with no social skills or talents, who nonetheless gets flashes of awesomeness.
Awesome Music: The film features a great soundtrack filled with memorable songs from the 80's and 90's.
Notable examples include "Canned Heat" from Jamiroquai while Napoleon dances, as well as "The Promise" by When In Rome, which plays over the credits.
Crosses the Line Twice: Shooting a cow in the head isn't funny. Shooting her while a school bus full of children passing by is.
Epileptic Trees: Napoleon has been armchair diagnosed with autism, Aspergers, compulsive lying, and just about every personality disorder under the sun. While a lot of his behavior may suggest Ambiguous Disorder, his habits could just as easily be ascribed to regular quirky behavior, offbeat small town dynamics, and Rule of Funny. Nonetheless, some viewers persist in finding a deeply disturbing meaning behind Napoleon's weirdness.
Jerkass Woobie: Napoleon might get beaten up less if he wasn't so rude to his bullies when they ask him simple questions. Though since they often beat him up without being provoked anyway, he probably has a right to be a jerk at them back. It's kind of a chicken-or-egg thing.
Squick: The farm lunch scene. Sandwiches covered in flies? Nummy! How about orange juice infused with raw egg?
Values Dissonance: Use of the word "retarded" started to come under heavy scrutiny in the 2010s, generally seen as unacceptable and very offensive, so Napoleon using the word at one point can be very jarring given how the film otherwise makes heavy use of Gosh Dang It to Heck! and is rated PG.
Jerkass Woobie: Uncle Rico. In the Animated Adaptation he is despised by pretty much by everyone. At the end of one episode it's revealed that he is a very sad and lonely guy.
So Okay, It's Average: Consensus is mixed like the movie it was based on. Also it didn't stand out much between the much revered Bob's Burgers and the much reviled Allen Gregory both airing around the time it debuted, and the series was quietly cancelled after six episodes.