Marlow´s difficulties as skipper on the trip upriver were that he had to repaired the bote, he had to drive it, he was horrified about becausehe saw this trip like returning back in time like to a prehistoric age because of the precarous lifestyle of the people there, he had to deal deal also with the hard treat of the climate and nature of this tropical zone, where rains are constant, hot weather dehydrates them at every time, some insects can be mortal for a human if they bite them, it was a really tough journey that he had to do.