That's what much of the book is: Marlow talking about Kurtz, first because of the curiosity he had about this man he was searching for and then because of the admiration he forms for Kurtz's final words. And that reminds me of how Nick spends the length of The Great Gatsby talking about Gatsby. First he is curious who this man, whose name is spoken so much and in such a specific way, is; and then he is fascinated by Gatsby's ability to hold onto and look up to the green light--however you interpret the green light.
With their reactions to the world, both men (Kurtz and Gatsby, not the narrators, that is) die in the end. And I wonder, are their reactions similar or completely opposite? Kurtz acknowledges what a great lump of chaos the world is and that it cannot be easily smoothed out. He calls that horror, which is the complete awareness of what there is to fear (as opposed to terror, which is when you don't know what it is that you're afraid of). I think Gatsby also recognizes that the world is not simple and does not always go the way you want it to go: his plans to gain back Daisy only work up to a certain point. And then along comes someone to kill him while he ponders and he hardly seems phased by it, he just seems to take it in stride as the natural next thing to happen. Is that a sense of horror? Gatsby seems to acknowledge the world as horrific, but to take a more passive view to it all than Kurtz does.
Maybe the difference is because Gatsby, not long before, thought he was about to achieve all that he wanted; he was a man with a shattered dream. Kurtz, on the other hand, was just a regular man who went out into the world (aka the European presence in the Congo) and found out what it is made out of. So for Kurtz, acknowledging that this world of imperialism is not good is a big step and an important one. Gatsby is a disappointed man, who I think want wants to still live in the part of his mind that created his dream; the importance of his perspective is not so much that he saw the imperfection of the world but that he knew what it was to dream of something more.
I think a further study of these two perspectives could be nice. It is absolutely essential to see what Kurtz saw: to see that the world is tarnished and fallen and corrupt and many things that contrast with what is good and beautiful. But then it is also necessary to be able to dream: only through the eyes of dreams can we, from day to day, spread the difference of light onto the chaos.