When the boat arrives at shore and the group come out of the sea, Billy walks after Peterson and stops just behind him. In the next shot, shown from the front, Billy appears on the left side of Peterson.
When Billy, Peterson and the driver push the car for the first time, there are four suitcases tied on its rear. When they do it for the second time, there are only three higher suitcases and when the car falls off the cliff, the four suitcases from the beginning reappear.
When we see the newspaper article about Vanmeer's murder, early in the film, only the first paragraph belongs to the story; what we can see of the second and third paragraphs is about a need for new school buildings.