The Heart of Darkness- analysis

The Heart of Darkness was a hard read for me, but overall it does have a lot of hidden meaning and symbolism, which I really enjoyed. First, the characters:
Marlow: like I said, Marlow is the Clint Eastwood of the story. He is intelligent, strong, maybe even a little rigid. He's also the middle man. Conrad wanted to teach the dangers of imperialism without being completely blatant, and Marlow allows this to happen. Marlow doesn't necessarily give in to imperialism, but he doesn't outright oppose it. Yet, he relates his story to all that will listen, so he clearly was moved by his story, as Conrad hopes the readers will be. The average reader should be able relate to him.
Kurtz: Kurtz is really the villain of the story, yet he is extremely clever. Marlow often refers to Kurtz as "hallow" (I marked it each time he did.) Hallow almost seems like a bad thing, but to me it seemed more like a mask. Kurtz seems to have no true identity. Therefore, he could be anybody. I think Conrad wanted to show that when it comes to imperialism, anyone can be the villian.

Now I have to discuss the title of this short story; I basically think it is brilliant. It took me awhile to understand it though. The heart is the "core" of a human, just as darkness is the "core" of imperialism. Though a heart, even consumed in darkness, still continues to beat and to live, the same applies to imperialism. Though so many suffer, a few benefit. Imperialism centers around helping the dominant, white male and though the heart is consumed in darkness, it continues to beat.

Annotating:
So I read Mrs. White's blog and liked how she underlined the words about darkness, so I did that. I underlined the synonyms of darkness in pencil, and I underlined my favorite quotes in pen. The other books I read, I tried to use a specific annotating structure, but for this short story, it didn't seem to be about the character development or word choice as much as the overall effect Conrad wanted to leave with the reader. Conrad uses a few strong phases for emotional effect, and those are the quotes I would underline, the quotes that tug on the heart-strings just a little bit.