Marlow listens to Kurtz talk while he pilots the ship, and Kurtz entrusts Marlow with a packet of personal documents, including an eloquent pamphlet on civilizing the savages which ends with a scrawled message that says, “Exterminate all the brutes!” The steamer breaks down, and they have to stop for repairs. Kurtz dies, uttering his last words—“The horror! The horror!”—in the presence of the confused Marlow. Marlow falls ill soon after and barely survives. Eventually he returns to Europe and goes to see Kurtz’s Intended (his fiancée). She is still in mourning, even though it has been over a year since Kurtz’s death, and she praises him as a paragon of virtue and achievement. She asks what his last words were, but Marlow cannot bring himself to shatter her illusions with the truth. Instead, he tells her that Kurtz’s last word was her name.
Literary critic Harold Bloom wrote that Heart of Darkness had been analysed more than any other work of literature that is studied in universities and colleges, which he attributed to Conrad's "unique propensity for ambiguity." However, it was not a big success during Conrad's life.   When it was published as a single volume in 1902 with two more novellas, "Youth" and "The End of the Tether", it received the least commentary from critics.  F. R. Leavis referred to Heart of Darkness as a "minor work" and criticised its "adjectival insistence upon inexpressible and incomprehensible mystery".  Conrad himself did not consider it to be particularly notable.  By the 1960s, though, it was a standard assignment in many college and high school English courses.
Atrocity heaped upon atrocity as Congolese lives were sacrificed in their millions to Leopold’s greed. With most able-bodied men conscripted into the state army or forced to collect rubber deep in the forest, the villages had few people left to plant and harvest food, hunt or fish. Inevitably famine spread, the birth rate plummeted, and a weakened and demoralised people fell prey to disease. Male rubber gatherers often died from exhaustion, while the women hostages starved to death. Tens of thousands more died in unsuccessful uprisings against the regime. Meanwhile bucket loads of severed hands piled up as a consequence of the failure to meet unrealistic rubber quotas.