Heart of Darkness Setup

I think that the way story opens out there will be a lot of flashback reading.  Marlow is already shown to have a flashback to back to when he was a sailor, sailing through Asia for 6 years and other stints in Africa.  I feel that his story will obviously be the main one but the other 4 people on the boat with him aren't there just to fill up space but to maybe let Marlow's new present character develop so we the reader can digest the information from his past and his present.  Maybe that contrast will give the character not more life but in a sense shine a brighter light and put a different perspective towards what he does and how what he does, whether it will mimic what he did in his stories or not.