Shrek was a behemoth of a movie for many reasons, but a lot of the early support for the film came from Eddie Murphy's sidekick character Donkey.
This first film in the series took four and a half years to make. It shows. Few films are as meticulously planned and well structured. Strangely enough, the main actors never met each other during filming, but the chemistry is definitely in place. Don't dismiss this as just a children's film.