Which flaw did you think most contributed to this being a bad movie?
This is a truly bad movie with lots of problems - unremarkable dialogue, melodramatic and hackneyed use of tired characterizations and plot contrivances ("he's so pure! he's so crazy! war is bad!"), the inability of the actors to perform with convincing accents - but personally I think the greatest flaw is the music.
The music for this movie is completely inept. Scenes that should carry on dramatic weight are constantly backed with music that not only detracts from the scene, it actively damages the scene. As an example numerous scenes that are meant to be tense are for some reason scored with a peppy marching beat and lilting horns. Just incompetent.