There is some fantasy to be found, but this movie is more focused on the Human condition, on the trials and tribulations we often encounter as older children.
The movies starts with what I found to be an incredibly stirring opening scene. We follow Jess as he goes about doing the 2 things he most loves...running and drawing. After a few moments his drawings start to come to life, even flying around him as he runs through countryside. with an incredibly moving main title playing in the background, this is the look, and feel, and sound of imagination set free, of limitless possibilities, of what being Human is all about. I knew from these first few minutes that this was going to be something very special. It was, from beginning to the final fade out.
The movie's main theme is, as the movie title suggests, a bridge...the bridge we build to connect with another. It is shown to be the magical process that it is, as we watch Jess and Leslie become best friends. It is all the more magical in that both Jess and Leslie are, more or less, loners, outsiders. By building a bridge between them, this encourages them to build bridges with others. Leslie befriends a misunderstood 8th grader, Jess reaches out to a teacher that he likes (for those who think it's inappropriate, you are cynical and paranoid). It really is something beautiful to watch..and listen to, as the soundtrack is quite amazing.
Oh, for those out there that think this is not a movie for children (age 8+ should be fine IMHO), give children some credit and stop trying to protect them from EVERYTHING.