I just caught this movie on big screen (IFC theater). Trier succeeds to irritate the viewer (almost as strongly as his Breaking The Waves).
This is the prologue, I was surprised to find it unedited on YouTube (soon it will be removed I'm almost sure). I will not comment on the movie now... but I enjoyed this prologue, first the almost still B&W pho(cinema)tography, the annoyingly -malignant- peaceful mood (despite the disturbing content).
Notice the analogy of the face of the falling kid with the "falling" father towards the end, also the orgasmic satisfaction after the fall.... this is just the start of the movie.
Trier is even irritating in dedicating the movie to Tarkovski (a very christian movie maker).