"I must say that part of the blame should go to ALL the publicity, the synopsis and trailers ... they all have kind of given the essential surprises/uncertainty away."

I recently watched the American trailer and I have to say that you're right. While establishing the main predicament should not be considered a spoiler (that's what the film is about), going any further than that could be harmful. Many have mentioned a certain Bresson film in their reviews which can also lead the viewers to make a few prejudgements.